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Toyota Sunrader 4x4 Conversion Project


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Five years ago I purchased this 1990 Toyota Sunrader 18' with the 3.0 V6. It had only 68,000 miles and was in excellent, well maintained condition. Every appliance worked, nothing was out of sorts, so I drove it sight unseen from Colorado Springs back to Reno, and it ran perfect the entire way.

At the time I didn't quite realize how rare the 18' V6 Sunrader actually was; there were only about a dozen made - more rare than the 4x4 which only came as a four cylinder. In these past five years my lady and I have taken this rig all over the West on dozens of adventures, and it has never failed us one time. The rig is as solid as an old Toyota can ever be. Now I am finally getting time to do the big project - a 4x4 conversion with a five speed manual transmission.

The main purpose of this swap is easily being able to drive in snowy/slippery conditions so we don't have to 'chain up' on the freeway. Even with the current BFG all-terrain tires, the 2wd platform for a rig this heavy with all its weight towards the back makes it rather sketchy on steep descents. Going over Teton Pass last winter with ice and snow on the road and locals tailgating the hell out of me was terrifying. The brakes are so powerful they can lock up the wheels easily, the 4 speed automatic transmission not only kills any available power the 3.0 has, but it also is not geared nearly low enough for confident engine braking downhill in slippery conditions, and the suspension has such little travel that the rig regularly bounces off its front bump stops.

The plan is to swap in a solid front axle from a 1985 Toyota 4x4, a R150 5 speed transmission and stock transfer case from a 3.0 V6 powered 4runner, regearing both axles from 4.10 to 4.88, installing a three inch lift with leaf springs, and running wheel adapters from 6x7.25" bolt pattern to 6x5.5" bolt pattern on the stock 1 ton full-float rear axle. I'll be running 33" all-terrain tires on 16" rims, going single rear wheel instead of duallys.

I have a 1985 4Runner that I built from a stock truck into a rock crawler years ago, so I know my way around old Toyotas pretty well. Wanted to document the process for anyone who is considering this project. Here we go!

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There is a YouTuber couple that attempted something like this (actually, a bit simpler) and the biggest issue (out of a myriad of issues) as I recall was getting axle ratios to match.  Basically, matching a 1/2-ton front axle to a 3/4-ton rear.  I recall that after they finally put it together, they experienced a catastrophic failure on the freeway (the axle didn't fail, but one of the dualies came off the RV).  

Anyway, they drove it around for a very short time but were too scared after that so they finally sold it and I think they went back to a Tacoma or Tundra truck with a camper.

Me, being the Debbie Downer I am, cannot understand why you'd want to take your house off-roading, but that's just me.  And having lived in snow country know that 4-wheel-drive does NOT help in slippery conditions I don't think the expense of adding 4WD to anything is worth it.  I also think, for resale value, keeping these old things as original as possible is the best way to enjoy the way they were meant and get the most value out of them.

That's my definitely-downer 10 cents, but only today it's free!  Merry Christmas!

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Sounds like a great project. Did you buy this from Jason? He sold his Sunrader about then and he lived in Colorado Springs. I helped him buy it in Texas. Not physically but you know , advice about it. Looking forward to your posts about the work your going to do. 

Linda S

Maybe more than a dozen built. There are 2 just in my little town in northern Cal, but still pretty rare and going to be worth big bucks when your done for sure

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You need a good workspace for this job. Unfortunately I don't have a shop, but I do have a giant side yard where I park the Sunrader. It's crushed rock, so I just bought some OSB 4x8 sheets at Home Depot, screwed em together and VIOLA...I got a flat workspace. Now I just gotta hope it doesn't snow or rain a bunch here in Reno in the middle of winter! 6 Ton jackstands were placed between the body mount front/side body mounts and transmission crossmember. You don't want the stand too close to either, because you'll be mounting the new spring hanger shackle under the body mount and you'll be cutting out/replacing 2wd crossmember with a 4wd crossmember. 
 
Taking apart the front end of the Sunrader was pretty straightforward. The quickest easiest way to do this is to just leave everything attached to the frame and go at it with a plasma cutter. But then you have a massive heavy hunk of metal on the ground to move. Since I wanted an easy access working area, I just disassembled the front end. I started by disconnecting the battery, removing the front bumper and grille, pulling the mass airflow sensor and entire intake assembly to the throttle body and the coolant overflow bottle. Then I went at the steering, loosening the tie rod sleeves so steering was disconnected from steering knuckles. Drained fluid and removed power steering lines at the pump. Removed idler arm, steering box and stabilizer. I cut the inner fender skirts so I had better access to the box, you gotta cut the skirts anyway to fit new shock towers, just make sure to not cut any fuel, electrical or hydraulic lines! I then removed trans cooler and trans cooler lines.
Removing front suspension started with disconnecting brake line at caliper (I disconnected at hard line/rubber line connection at caliper so I could pinch the rubber line with hose clamp to avoid fluid loss until I replaced the line with a new stainless braided steel line). Removed shocks. Then loosened torsion bars. Bolts are located on the 2wd transmission crossmember inside the frame rails. You'll need a wrench on the jam nuts to hold them in place as you back out the long tension bolt with a breaker bar. Lubricant on the bolts is your friend. This is where an east coast/rusty truck SUCKS, as the bolts are probably seized. You might need a few days of PB Blaster and/or a torch to heat them up. West Coast/desert folks, you're stoked. No problem.
Remove two 17mm bolts from upper A-arm, bolts are located inside the frame rail. These are a bit tricky to reach. This is where cutting the inner fenders helps a lot. For me, on the 3.0 V6, the passenger side fender skirt has a bunch of vacuum switches bolted to the skirt, so I had to unbolt and move them away in order to reach the upper A-arm bolts.
Remove three 17mm bolts holding the lower ball joint to the lower A-arm.
Loosen two 14mm bolts holding torsion bar on lower A-arm, then loosen big nut on front of lower A-Arm. Tap bolt rearward, which will dislodge the torsion bar from the A-arm. Pull lower A-arm bolt out, then remove lower A-Arm. Pull on torsion bar to remove once A-arm is removed.
With 17mm bolts removed from upper A-arm mount next to engine mount, upper A-arm along with the entire knuckle/wheel hub assembly should lift out. Again, cutting inner fender skirt will help with clearance.
Now you should be left with the 2wd suspension mounts welded to the frame.
Pull our your saw and angle grinder, or to make it really easy, plasma cutter and go to work. Frame rails should be clean so you can mount the new shock towers as well as the 4x4 IFS steering box (you'll want to buy the steering box brace/mounting kit from All-Pro, Marlin or Trail Gear).
If cutting, I highly recommend the Diablo heavy metal reciprocating saw blades with carbide steel. Not cheap ($15-$20 per blade) but very tough and durable and cut through all the metal without much issue. Cut as close to the frame as you can without cutting into the frame. The closer you cut, the less grinding you have to do. BE VERY CAREFUL to not cut any fuel, electrical or hydraulic lines. There are a few in the way, especially on the passenger side. Be sure to clearance any lines before cutting.
I don't like inhaling airborne grinding wheel abrasives, so I wear a respirator, and to avoid getting metal cuttings in my eyes/hair, I wore a hoodie sweatshirt and ski goggles. Let's you get right up in there close to your work area.
Next was removing transmission, which was pretty straightforward. But before I did that, I removed the Doug Thorley headers I had on the engine and cut out the exhaust which crossed underneath the transmission. I am going to need to redo the exhaust anyway, and with the entire front end of the truck removed, getting at the headers was easy, so I pulled them.  
 
Then I drained the trans fluid, removed the trans dipstick tube riser (plug the lower half of dipstick tube opening with something) and removed rear driveshaft bolts at the coupler/collar between trans and rear diff. The rear part of the shaft will drop down, then you can unbolt the intermediate shaft from the crossmember collar and simply pull the output shaft out of the back of the transmission. Then I removed transmission bellhousing and starter motor bolts. To keep track of how the bolts go back in, take a piece of cardboard and mimic the bolt pattern of the bellhousing, taking each bolt and sticking it through the cardboard in the pattern they're supposed to be. I then lifted the trans a little with this handy trans jack from Harbor Freight. Only costs $75 with coupon and will be very clutch for other jobs like mounting the differentials. Once the trans is lifted enough, it will take weight off the crossmember, then you can remove the bolts from the trans crossmember mount. Pull back on trans and be ready for more fluid to come out of the torque converter. Getting the trans out was a little tricky, as the crossmember is not removable and it prevents the trans from pulling back far enough from the engine to drop it. Instead of wrestling with it, it was much easier to just remove the six bellhousing bolts from the trans, then it dropped right down no problem. Disconnect wiring plugs from trans. You won't end up needing the wiring harness, so you'll cut out most of the wires, but there are a few wires you'll need that I'll get into later. Removing the torque converter was straightforward, there are six bolts that connect the starter flywheel to torque converter. Remove those, then you'll remove the 8 bolts connecting the flywheel to the crankshaft output. 
 
I was delighted to discover the rear main seal on my 3.0 V6 was absolutely clean...not a drop of oil coming from it! At 100k miles, this 3.0 V6 is rock solid. Doesn't leak or burn a drop of oil. So at least for now I'm keeping it...although now would be a good time to do a motor swap! Tempting, but if it ain't broke, don't fix it.
 
Next was cutting out the 2wd transmission crossmember, which was kind of a beeyatch. There's not a lot of room to work a sawzall or cutoff wheel, so you gotta be careful, especially on the passenger side as there are fuel and brake lines running right where you need to cut. I loosened the brake and fuel line mounts from the frame and moved them inboard enough that I could get in there with the saw. It took a good hour, a lot of cursing and a broken saw blade, but I got the crossmember cut out. Oh, and I also had to cut the ebrake mount off the crossmember, so now the ebrake cable is just hanging loose. I'll fab up a new ebrake cable mount on the 4x4 crossmember when it goes in.
 
Now I have a nice long, open hull ready for the new 4x4 transmission to go in! Just waiting on some parts and I'll get to the next steps in a few more days. About 20 hours of work invested so far. Started snowing this morning, so I'm shut down for a little but, but looks like we'll be getting a dry weather window here in the Sierra Nevada for a few weeks so I can get this thing back on wheels!
 
 

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Edited by Genshie
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Man Lopez your are Debby Downer. 4x4 makes a huge difference in slippery conditions. That's why 2wd vehicles need to chain up in snow in the Sierras but 4x4's don't. They live in Reno. Not having to chain up is a biggy. It's cold out there. 

As to why they would want to go off road in their camper, well everything worth seeing is not visible from the highway. I have pushed my 2wd to the limit trying to get father back into the woods to see new things. Can't do Rubicon but I can get to where it starts and that is supposed to be 4x4's only. The adventure is everything

Linda S

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15 minutes ago, lopezg273 said:

There is a YouTuber couple that attempted something like this (actually, a bit simpler) and the biggest issue (out of a myriad of issues) as I recall was getting axle ratios to match.  Basically, matching a 1/2-ton front axle to a 3/4-ton rear.  I recall that after they finally put it together, they experienced a catastrophic failure on the freeway (the axle didn't fail, but one of the dualies came off the RV).  

Anyway, they drove it around for a very short time but were too scared after that so they finally sold it and I think they went back to a Tacoma or Tundra truck with a camper.

Me, being the Debbie Downer I am, cannot understand why you'd want to take your house off-roading, but that's just me.  And having lived in snow country know that 4-wheel-drive does NOT help in slippery conditions I don't think the expense of adding 4WD to anything is worth it.  I also think, for resale value, keeping these old things as original as possible is the best way to enjoy the way they were meant and get the most value out of them.

That's my definitely-downer 10 cents, but only today it's free!  Merry Christmas!

Yeah, I read about them. Quite frankly, they didn't know what they were doing. They spent all this time making the inside of their Sunrader super awesome, but spent no time actually addressing the most important stuff - namely - making sure the drivetrain was bulletproof. I think they were so over invested time and money wise into the entire project that they just gave up and sold it. The new owner is stoked, because if the new owner knows whats up, they can fix the issue very easily and have a super nice Sunrader! They didn't explain exactly what happened, but from the sound of it, it seems their wheel hub studs were not tensioned correctly and the studs sheared off. With new wheel hubs, you have to tension the wheel, drive it for 30-50 miles, then retension again, and possibly one more time after that. Anyway, it was pretty evident they didn't know what they were doing.

You can't understand why I'd take my house off-roading? Really? Off roads is the best place for a rig like this, because there are no other RVs out there and essentially this is a Toyota minitruck...aka...one of the best off-road rigs ever built. Plus, that's where all the best free boondocking is. I'm not gonna be getting radical or anything in this rig, but having 4WD is quite nice when you get into tricky spots, especially in sand. Anyway, different strokes for different folks, but out here in Nevada, all the goods are off-pavement. So that's where this rig has been going...and it has done pretty damn well for a 2WD.

As far as 4WD and snow, I can tell you for absolute certain that 4WD in the snow works infinitely better than 2WD, particularly when going downhill. Four wheels engine braking downhill is always better than two. Plus, with a 5 speed transmission, I have much better engine braking control so I don't have to use the brakes. Bottom line, this RV will drive/handle so much better on a 4WD platform with more suspension travel, better balanced weight (added weight up front) and bigger, meatier tires with better traction. 

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Hi, 

 I just noticed your post. I'd like some info on the wheel adapters you mention, I have a 85 Granville that has had the engine and transmission swapped to from a 22r with an automatic transmission to a 22re with a 5 speed manual and I have thought following up with a 4x4 conversion for years now. Looking forward to seeing your process

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38 minutes ago, linda s said:

Sounds like a great project. Did you buy this from Jason? He sold his Sunrader about then and he lived in Colorado Springs. I helped him buy it in Texas. Not physically but you know , advice about it. Looking forward to your posts about the work your going to do. 

Linda S

Maybe more than a dozen built. There are 2 just in my little town in northern Cal, but still pretty rare and going to be worth big bucks when your done for sure

Hey Linda, no, I bought it from a guy named Bob (or Bill?) in Colorado Springs. Very nice guy. Air Force pilot instructor. He took meticulous care of it. I believe he bought it from someone in Southern California. I flew in from Reno, he picked me up at the airport and went back to his place where it sat. It was better than it looked in photos, which is rare. Dashboard and interior were immaculate. Almost new. I was so stoked! At the time I thought was paying a bit much for it ($12,500), but looking back, I think it was a steal. Drove all the way back to Reno without a single issue. Just barely made it before a snowstorm hit the Rockies. Such a great first adventure!

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7 minutes ago, travel-toy said:

Hi, 

 I just noticed your post. I'd like some info on the wheel adapters you mention, I have a 85 Granville that has had the engine and transmission swapped to from a 22r with an automatic transmission to a 22re with a 5 speed manual and I have thought following up with a 4x4 conversion for years now. Looking forward to seeing your process

There's a company here in Reno called Motorsport Tech that makes wheel adapters for virtually anything. They've been doing it for 30 years. The owner told me over the phone he's done some other adapters for Toyota RVs. I'm gonna take him my entire wheel hub so I know for sure that the adapter setup will be bomber. 

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On 12/23/2019 at 2:22 PM, Derek up North said:

I believe they made that adapters for 'Atlas'. Around $450/pair.

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Am I only the one that finds those wheels horrendous the Sunrader? Looks like a disproportionate matchbox car. 

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44 minutes ago, Derek up North said:

Some love it. Each to their own. :)

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Don’t get me wrong, I’ve built my fair share of big trucks, these wheels just don’t look right on the sunrader to me, of course that is just my opinion and worth exactly that.  That 4 banger has a hard enough time pushing that camper, those huge wheels probably suck up a few more hp! 

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  • 2 weeks later...

The next phase of the Sunrader 4x4 project was installation and fabrication. I started by ordering and installing a 35 pound flywheel and performance clutch kit from LC Engineering. This particular flywheel is about 10 pounds heavier than the stock one designed for the 3VZE 3.0 V6 engine, which will vastly help the Sunrader maintain uphill momentum. I had a heavier than stock flywheel on my 4Runner back when it had its original 22re engine, and the uphill performance increase was noticeable thanks to the greater inertial momentum of the heavier flywheel. It also enables the engine to run down below 400 RPMs in low range without the engine stalling, helping in very slow speed situations.

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After installing the flywheel and clutch, while I still had room underneath the truck, I drilled out the holes in the frame where the new shackle tube sleeves will go, connecting with the back of the leaf springs. This was a little tricky, but thankfully the IFS Eliminator Kit from Trail Gear has handy stainless steel templates you clamp in place. They recommend using a plasma torch which makes the job really easy, but all I had was a 1 3/4” hole saw, which worked just fine. Make sure to get the highest quality hole saw you can and use cutting oil to keep the hole saw from overheating and going dull. The biggest pain was once the outer holes were cut, there's still some metal on the inside of the frame rail that needs to be cut. It was a bit awkward, but some careful use of the reciprocating saw and a little more hole sawing took care of it. The sleeves went in perfectly with the 1 3/4” bore, just make sure they are dead straight before you weld them! It's deceiving what is straight because where the tubes go through, the frame is angled.

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After getting the tubes in and centered, I welded them in place, then while I had the welder out, I welded on the front spring hanger. I positioned the hanger 1/8 inch forward of the frame so I could get good weld purchase between the two surfaces, laying two inch weld followed by a two inch break before another two inch weld. I also cut the very bottom of the frame where the two frame rails meet the cross rail at the front, so the spring hanger sits flat on the cross rail without any gap.

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I then installed the transmission and transfer case, and mocked up where the new 4x4 crossmember goes. Supporting the transmission with a jack, I bolted the crossmember to the transfer case, then figured out where the crossmember needed to go. On 4x4 trucks the crossmember is actually offset to the driver side, so the outer two mounting bolts are outside the frame rail on the driver's side, and on the passenger side, the outer two mounting bolts are actually flush under the middle of the frame rail. So don't make the mistake of trying to center the crossmember under the truck or else your transmission will be crooked. No bueno.

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I fabricated two new 90 degree bend mounts with a center gusset, one welded to the outside of the frame rail on the driver's side and the inside of the frame rail on the passenger side. For the other four mounting bolts, I drilled holes in the bottom of the frame and welded four 17mm nuts into the frame. The nuts I had leftover from disassembled 2wd front suspension. Getting the crossmember just right was rather time consuming, but it came out great and now the crossmember bolts in perfectly, just like the OE setup.

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I then had to figure out how the stock e-brake was going to reconnect, and it actually came together pretty quick. I took the leftover front cross brace from the 2wd suspension connecting the left and right side, cut it in half, then welded it to the back of the crossmember. It just so happened to be the exact right size to fit the spring and lever of the stock e-brake cable.

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Wiring was pretty straightforward. Under the hood there is a harness that ran to the automatic transmission. I cut the entire harness, then disassembled it to get the wires I needed. Most of the wires go to the switch on the transmission that indicates gear selection. Most of the wires do not get reused if swapping to a manual transmission, but there are a handful that do.

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You'll have to verify wire color depending on your year truck, but for my 1990 Toyota, I needed to reconnect four wires for the oxygen sensor (pink w/ green stripe, brown, white w/ red stripe and a gray wire with outer wire shielding covered in a black sleeve), reverse light wires (black w/ orange stripe and red w/ white stripe) and the neutral start switch (black wire and black with white stripe). I ran two new wires separate from the harness into the cab for the 4x4 switch light. There is also a black w/ white stripe wire that connects to the starter. It was spliced into the black w/ white stripe wire to the neutral start switch, so I just spliced it back into the neutral start switch wiring. With the neutral start switch wiring connected, the ECU thinks the transmission is always in park, so the engine will start.

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I decided not to wire in the start cancel switch from an OE manual transmission because I always depress the clutch before starting anyway. Also, it can be handy sometimes to use the starter to inch the vehicle forward when in first gear and low range. I have not yet sorted out the cruise control, but I plan to wire the clutch switch into the cancel circuit on the cruise control so that when the clutch is depressed, cruise control will turn off. More on that later.

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Next was installing the clutch pedal and master cylinder, which was quite easy. I just got the entire pedal assembly from the same generation 4x4 pickup and it bolted right in. Both the automatic pedal assembly and the manual pedal assembly have a template already there for you, so you know exactly where to drill your holes. One note – I drilled my holes before pulling the automatic pedal assembly, which I shouldn't have done, because it just so happens the manual pedal assembly has the holes inboard about ½ inch, so I had to cut the pedal assembly in two in order to use the holes I already drilled, so now the brake pedal and clutch pedal frames are separate. No big deal, but for future reference, don't drill the holes until the manual pedal assembly is in.

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Since the front spring hanger and shackle tubes were in, I decided to hang the springs and get the axle housing underneath, which is definitely the turning point of this project. I was seeing the new front end taking shape quickly!

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Next was mounting the steering box. The IFS Eliminator Kit from Trail Gear is very complete, but it did not include the IFS steering box brace kit, which you absolutely need for crossover steering. The kit is about $65 and comes with two plates, sleeves and bolts. You have to mount the IFS 4x4 box as far forward on the frame rail as possible. To make install easier, I cut the fender skirt up high. One of the preexisting sleeved holes from the 2WD steering box can be reused, only requiring one more hole to drill for the front bolt sleeve. The third sleeve sits on top of the frame rail. I welded it all up and the box slides right into place.

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The shock hoops were next. This is a little tricky because the hoops that came with the kit are rather tall, so I decided to cut the fender skirts high and mount the hoops inside the engine compartment versus outside the fender skirt like a stock setup. I like this better anyhow because cutting the skirt high makes accessing engine components like the header bolts, oil filter and starter motor super easy. Plus, mounting the hoops inboard gives the shock a nice angle once mounted, just inboard of vertical. It is important to either plate the frame where the hoops will be welded, or use the small tubular braces that come with the IFS Eliminator kit. I was able to mount the braces from the hoop, connecting to the frame right at the motor mount. It looks super clean and symmetrical while still allowing for plenty of access from the side into the engine compartment.

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Everything so far has gone pretty smooth. Fabbing the crossmember mount was definitely the trickiest job so far. And the only SNAFU I've had was discovering I had the wrong bellhousing after the transmission had been mounted back in place. Apparently this R150 trans had a 5VZE bellhousing on it with the clutch fork on the driver's side. I figured out the problem once I test fit the Thorley headers, as the fork sat right in the header's path. Wasn't a huge setback, thankfully I did the test fitting before everything else was installed. I quickly pulled the trans and got the right bellhousing, so maybe only a 2 hour setback. If that's the biggest challenge I face on this job, I'll be pretty damn happy!

At this point I am 65 hours of labor in. I estimated about 100 hours, so it seems I'm right on track, as I still need to go sprung over on the rear axle. And my original budget of $6,000 also seems to be pretty much on track. Hoping to get this beast on wheels in the next two weeks! Getting the axle under the truck was definitely an exciting moment. With 33” tires this machine is going to sit nice and tall, but not too tall. Once the springs settle, the hood should be just below chest height. Stay tuned!

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Wow very impressive work. Amazing your doing all this for only 6 grand. My son told me it would cost 5 grand to do a 4x4 conversion on my Sunrader and that was 10 years ago. Your labor of love will be worth somewhere around 50 grand when your done. Love it

Linda S

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Awesome

Lets see $6000 in parts, 100 hr labor (@$75 HR). $10,000 for the rig.  Good thing your doing this for the love of the game and not trying to make a living

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6 hours ago, WME said:

Awesome

Lets see $6000 in parts, 100 hr labor (@$75 HR). $10,000 for the rig.  Good thing your doing this for the love of the game and not trying to make a living

Well, you know how it goes, the more you do something the faster it moves. The second time around I could probably do it in 75% of the time, the third time, probably 50 -60 hours, but yeah, I wouldn't want to do this kind of stuff for a living. I love to tinker and fabricate and build stuff, but as soon as I'm getting paid to do it and there are timelines and expectations, it's no longer as fun. 

k

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Hello all. Im new to this group! Im doing the same 4x4 conversion except my sunraider is 4sp manual 22re. I have a 1985 front axle installed already. Clutch and trans is next!

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We owned a 86 Sunrader 4x4 turbo 4 IFS front. Main issue was weight. Reducing the interior coach weight could make a difference. We kept ours stock almost. Larger downtube from the turbo and 2 1/2 inch exhaust. Added extra leaf in the rear. When loaded for a week long trip it was heavy. Turbo with an automatic at high elevations? Sometimes could not get the turbo to spin up when in gear. Found that out by trying to back up onto a big rock to get level. Could not develop enough power to even try. First gear low was ok but reverse no way. I have to say though it did pretty well out on some sorta bad roads. My Bronco VS Sunrader

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4 hours ago, Gulfstream Greg said:

We owned a 86 Sunrader 4x4 turbo 4 IFS front. Main issue was weight. Reducing the interior coach weight could make a difference. We kept ours stock almost. Larger downtube from the turbo and 2 1/2 inch exhaust. Added extra leaf in the rear. When loaded for a week long trip it was heavy. Turbo with an automatic at high elevations? Sometimes could not get the turbo to spin up when in gear. Found that out by trying to back up onto a big rock to get level. Could not develop enough power to even try. First gear low was ok but reverse no way. I have to say though it did pretty well out on some sorta bad roads. My Bronco VS Sunrader

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You have me drooling at that bronco!

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21 hours ago, Gulfstream Greg said:

We owned a 86 Sunrader 4x4 turbo 4 IFS front. Main issue was weight. Reducing the interior coach weight could make a difference. We kept ours stock almost. Larger downtube from the turbo and 2 1/2 inch exhaust. Added extra leaf in the rear. When loaded for a week long trip it was heavy. Turbo with an automatic at high elevations? Sometimes could not get the turbo to spin up when in gear. Found that out by trying to back up onto a big rock to get level. Could not develop enough power to even try. First gear low was ok but reverse no way. I have to say though it did pretty well out on some sorta bad roads. My Bronco VS Sunrader

 

 

I can't even imagine how gutless a 4x4 turbo would be with that horrible 4 speed automatic. It's bad enough with the V6, which is why swapping to a manual trans was mandatory. And yes, I know what you mean about not having enough power to back up onto rocks, a curb or anything with the automatic. I had the same problem. I'd have to back into things with enough momentum to bump up over them. The trans wouldn't let the engine's power drive the wheels from a dead stop. Won't be a problem now with low range behind the 5 speed!

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2 hours ago, Genshie said:

I can't even imagine how gutless a 4x4 turbo would be with that horrible 4 speed automatic. It's bad enough with the V6, which is why swapping to a manual trans was mandatory. And yes, I know what you mean about not having enough power to back up onto rocks, a curb or anything with the automatic. I had the same problem. I'd have to back into things with enough momentum to bump up over them. The trans wouldn't let the engine's power drive the wheels from a dead stop. Won't be a problem now with low range behind the 5 speed!

The turbo trucks used the same trans that is behind the V6's with a locking converter. Ran it in overdrive all the time. If the trans was running hot out of overdrive you could engage OD and actually watch the trans temp drop rather quickly. I have a friend who has the same truck minus the sunrader coach. His though, manual trans and a hybrid turbo. His turbo spools up when cracking open the throttle. Huge advantage. Still though I would take the V6 over the turbo 4. Actually prefer a V8 for off roading. Just something about having torque. 

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10 minutes ago, Gulfstream Greg said:

The turbo trucks used the same trans that is behind the V6's with a locking converter.

I've read before that the 22RTE (turbo) used the A340 automatic and not the A43 automatic. I've also read that the 22RE (non-turbo) only connects to the A43. This leaves me confused. :)

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  • 2 weeks later...

 

 

After mounting the shocks, I reinstalled the original front sway bar, then fabricated a vertical mount from the lower shock mount to connect the sway bar. I recycled the old 7” long torsion bar bolts form the 2WD suspension, then reused the rubber bushings from the original sway bar connectors. While not a quick disconnect system, all I need to disconnect the sway bar are two 17mm wrenches, and the top nut comes off in under a minute. Quick enough and free.

 

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I moved on to fabricating a modified steering shaft connecting the steering wheel to the steering box. Because of the forward location of the new box, the stock shaft was a few inches too short. Again, some of the old 2WD parts came in handy. I used two threaded tie rod end sleeves from the old steering, cut the shaft, and bolted the two sleeves to either end of the shaft, giving me the added length I needed. The sleeves are thick and stout, and secured with bolted clamps. I figured if they're strong enough to hold together the tie rod ends, they're strong enough for a steering shaft.

 

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Next was reassembly of the entire front axle. Considering this procedure has been covered eleventy billion times on the internet, I'll skip ahead. 

 

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Steering came after reassembly of the front axle. The Trail Gear IFS Eliminator kit came with all the components needed – tie rod ends, tie rods, drag link and pitman arm. The first step to getting the steering and alignment right is setting the proper toe-in. For solid axle Toyota trucks, I've had great luck with 1/8” toe-in. Easiest way to do this is to clamp a straight edge to the brake rotor surface on both sides. On both sides, measure 18” forward and 18” rearward of your wheel hub center, then mark each point. To set toe-in, run a tape measure from the driver side to the passenger side, first on the front marked edge, then on the rear marked edge. Take a measurement of each, then either tighten or loosen the tie rod so the front edge measurement is 1/8” narrower than the measurement of the rear. It will take a few tries. Once you get it exactly 1/8”, tighten the jam nuts, making sure to not let the tie rod turn.    

 

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Once toe-in is set, then you can set the length of the drag link from the passenger side steering arm to the pitman arm. Find the steering box center, then the steering wheel center, and adjust the drag link accordingly, tightening the jam nuts last.  

 

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Next I installed the steering stabilizer. Because of how much clearance under the engine I have, I was able to mount the stabilizer on top of the axle housing, connected to the tie rod. The flatter and more linear you can get the stabilizer, the better. Under suspension compression, the tie rod and drag link are very close to each other, but they clear by just about 1/2”, so there is no contact. I used the mount plates and urethane front bumps that came with the Trail Gear Kit, and welded the mount plates under the frame. I will better dial in the bumpstop contact point once I get the truck on wheels so I can see how the suspension is flexing and determine how much up travel I need. I cut the front spring u-bolts shorter, but kept them long enough so I could mount another plate above the u-bolt plate in case I need to shorten the length between bumpstop and axle.

 

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With the front end pretty much buttoned up, I moved onto converting the rear sprung under axle to sprung over. After supporting the rear axle, removing the shocks, sway bar links and u-bolts, I dropped the springs by pulling the front spring mount bolt and the rear shackle bolts. I bought new spring perches and placed them on top of the axle, then dropped the axle down so I could reinstall the springs, but first I had to flip the spring pack pin so it would fit properly into the spring perch (two giant vice grips work great to keep the springs compressed while removing the pin). The Trail Gear spring perches have three holes so you can run 1” forward, center or 1” back. I ended up running the axle 1” back so the axle was better centered in the wheel well to accommodate the bigger tires. And since the stock spring shackles are 5.5” eye-to-eye (2 inches longer than the stock Toyota 4WD spring shackles), I kept them.

 

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Once the springs were reinstalled, I set the pinion angle by rotating the axle housing. Setting pinion angle is a whole science unto itself, and how you set it depends on what kind of driveshaft you are using. I have a double cardan CV, so the procedure is to point the pinion straight at the output flange of the transmission. If you are using u-joints on both ends, you have to set the pinion differently so that both u-joints are perfectly in phase. I won't dive into this part, because it's well documented elsewhere.

 

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Once I set the pinion angle, I welded the perches to the axle housing. Because I wanted to run longer body Bilstein shocks in the back, I cut the old lower shock mounts off the stock u-bolts and welded them onto the now unused lower spring perch. The location is perfect for the shock and sits just below the level of the axle tube. Next was installing a u-bolt flip kit, then reinstalling the airbags. It took some measuring, cutting and drilling of new holes, but I got the airbags centered just right over the u-bolts.

 

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To make the stock sway bar work, I needed much longer links since the rear end is now almost a foot taller than stock. The old 2WD front end parts again came in handy. I used the two 1” thick horizontal brace bars that connected from the underside of both 2WD a-arm spindles to the front crossmember. One side of the bar has a threaded end with two jam nuts, a sleeve and two rubber pucks. I cut the non-threaded ends off, then welded them to the original rear sway bar link mounts. After opening up the holes on the upper link mounts, I slid the threaded end of the links through and they fit perfectly! Just the right length and the 1” thick diameter will ensure the rear end is tight with minimal sway.

 

I fabbed a bracket to lift the Load Sensing Proportioning Valve (LSPV) to its full upright position (maximum braking power), then installed a stainless steel brake line extension due to the lift.

 

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After reinstalling the drivelines, it was time to fab the exhaust. This was a bit tricky, particularly because I have Doug Thorley headers on this 3.0 V6 and have to build a crossover pipe that runs underneath the transmission. But I had to make sure that there was enough driveshaft clearance so it didn't hit the exhaust pipe. After a lot of cutting, measuring, fitting and tack welding, I got the bends just right and maximized clearance for the driveshaft.

 

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The trans and t-case shifters went in without any drama, and I used my old Hurst shifter that I've had on four different Toyota trucks over the last 20 years.

 

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For wheels and tires, I scored. Found a set of five 80 Series Land Cruiser rims and near new E-Rated BFG All-Terrains in 265/75r16 size, which is about a 32” tire – all for $850.

 

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Then I installed the rear axle adapters for the stock 1 ton Toyota full floating rear end. These are probably the most asked about part of the job. The custom adapters are made by Motorsport Tech in Reno, NV. They've been making adapters for everything from drag race cars to rock crawler trucks over the last 30 years.

 

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These adapters allow me to run a standard Toyota/Chevy 6 on 5.5” bolt pattern single rear wheel. And with the offset of the Land Cruiser rims, the outer edge of the new single rear wheel is the same track width as the original dually wheels. They fit the wheel well perfectly, and the rim is very snug on the hub, maintaining a hub-centric design.

 

 

 

 

Edited by Genshie
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Now it was time for the exciting part of the job, getting this beast off the jack stands and on the ground and on its first drive!

 

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Once it was on wheels, I immediately noticed the truck is 3 inches taller up front than the rear. There are a few remedies for this. First off, the Trail Gear 3” lift springs I'm using are known to settle 2-3 inches over time. Plus, I am adding a heavier front bumper and winch. Until the springs settle, I'm pulling the bottom two leafs out of the pack and running a 1” shorter front shackle. Then if that is not enough, a 2” longer shackle out back should bring the truck to balance.

 

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It was time to take the Sunrader on its first shakedown drive, a very exciting and a little nerve wracking moment indeed! Would it drive straight? Did I have all the bolts tight? Would something leak or explode? Only one way to find out.

 

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I took it for a 20 mile cruise to properly break in the new 4.88 rear diff with the Detroit Truetrac limited slip diff, and despite it being three inches too tall in the front, the truck drove straight, no death wobble at all, sway was no worse than when it was 2WD, brakes were strong and the truck cornered surprisingly tight thanks to the sway bars. The only issue was a driveline vibration between 45-60mph, but otherwise, everything seemed to be really well set up for a first try. The driveline issue should be resolved once I lower the front end and raise the rear end a little.

 

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I even took it for a little off-pavement test, inadvertently ending up in some nasty Nevada peanut butter clay mud, the stuff that paralyzes most trucks. I was a little hesitant, but figured, “what the hell” and went for it. Locked the hubs, shifted into 4WD low range and this rig walked right through it! It made my day. That mud would have left any other 2WD rig stuck for sure.

 

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The one thing I immediately noticed was the 35 pounds LC Engineering flywheel. Because of its heavier weight, in 4WD low range, you can let the engine lug down to as low as 300 rpms and it won't stall; a very nice feature when crawling at very low speeds. It makes things easier on the drivetrain and on the driver. So for anyone doing this swap with a manual transmission, I highly recommend spending the extra money on the heavier flywheel.

 

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I haven't taken the newly converted Sunrader 4x4 on a second drive yet. I'm going to remove a few leafs from the front spring pack, put a shorter front shackle on then see where she sits. Then I am going to fit a heavier front bumper to see if that levels it out. If not, I'll fab some slightly longer shackles out back and that should do the trick.

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So far I am about 120 hours of labor in on this project and $8000 invested. I went over my $6000 budget because I decided to buy new parts instead of trying to source used parts. Plus some of the upgrades like the Truetrac differential and the heavier flywheel/clutch kit were spendier than I budgeted for. Could you do this swap for $6,000? Sure. But I decided I wanted new parts that maximized the performance of this setup. Even still, $8,000 is pretty reasonable to build one of the most capable off-road RVs in existence.

 

That's it for now. I'll update again once I get everything dialed in. Got a 3,000+ mile Canada ski road trip coming in late February, so I gotta git-r-dun!

 

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  • 2 weeks later...

Great job!! Looks really good :) That rear spacer would make me nervious tho! Im swapping in a t100 rear end on mine to get the same result without a spacer. Mine is a 21ft and i plan to tow small trailer after I 3.4 convert it

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hey there. been following your build. great job. thanks so much for sharing. your rig is awesome. i am almost 70 years old, but can still appreciate a cool rig and all the talent, time and money it took to get "cool".   again , what a great job. joe from dover.

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  • 1 month later...

Just wanted to provide everyone an update on how the conversion has been running. Just got back from a 4,000 mile road trip to Canada and I'm happy to report the truck ran flawlessly! The only issue I encountered was broken front sway bar mounts about 500 miles into the trip. I didn't make the steel base plates thick enough and they tore through. But it turns out this truck runs very stable and didn't even really need a front sway bar, as I drove the remaining 3,500 miles without one! Some observations from the trip: 

 

Fuel economy went up - Previously averaged 12-14 mpg as a 2wd with the four speed automatic. As a 4wd with 5-speed manual, fuel economy rose to an average of 15mpg, sometimes 16mpg! Really happy about this unexpected improvement. 

 

Heavier LC Engineering flywheel is a must - the heavier flywheel and heavy duty clutch cost $750, but they are worth every dollar. Not only does the flywheel hold gears for longer on sustained climbs, but it allowed me to creep at very low RPMs through the snow in low range. Highly recommended.

 

Single rear wheel is so much better than duallys - The truck was stable and ran great the entire trip with 16" rims and E rated tires. Also, despite what some think because of previous folks who don't know what they're doing - putting wheel adapters on the stock 1 ton full floating Toyota axle to go single rear wheel is totally safe and works great. The Motorsport Tech 6x7.25 to 6x5.5 adapters fit perfect, never came loose and paired with the Toyota Land Cruiser FZJ80 16" alloy rims maintained the same rear track width as the stock dually setup. 

 

A 4x4 Sunrader devours snow - With a good set of snow-rated tires, because of its ideal weight, a Sunrader 4x4 is very stable and capable in snowy and slippery road conditions. Never had a problem in any parking lot we went where there were sometimes 1-2 feet of untracked snow. The Sunrader would drive right through it. 

 

A 4x4 Sunrader is the most capable RV in existence - I'm confident there's no other RV sporting a shower, toilet, oven, range, furnace, fridge and air conditioner that can go as many places as a 4x4 Sunrader, especially with a good suspension setup, low gearing and some traction aid devices in the axles. 

 

Aside from having to fab new sway bar mounts, the only other thing I need to do is either lift the rear a few more inches or lower the front a few inches, as it still rides a little tall up front. The Trail Gear 3" lift springs definitely lift the front end more than 3 inches. The stock rear Toyota springs work great sprung over as a 4x4, but to match the front you'll need to use either stock height front springs or Old Man Emu 2" lift springs. However, I will say that the Trail Gear springs ride great with Bilstein 5100 shocks. Not too stiff, just the right amount of ride quality. If I can get these springs to settle a little (gotta flex them out and work them in), I think they'll end up being the perfect height. 

 

Anyhow, thanks for following along. This project was worth every hour and every dollar. If you have the means and skill, I highly recommend doing it. You won't be disappointed! Oh, and take extra time everywhere you go because you will constantly be stopped and chatted up by people. Must have counted at least 100 thumbs up from folks on our trip. A 4x4 Sunrader seems to be everyone's dream rig!  Here are some pix from the trip.

 

 

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