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5 speed swap into 1978 Chinook, Marlin screw-up


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I realize this is kind of esoteric and only of interest to 70s truck owners.  But - I just discovered something kind of neat.

When I did my first 5 speed swap into a 1978 Toyota Chinook, I did what I thought was logical.  I used what Toyota used OEM at that time.  That means a W50 Aisin  five-speed.  This is almost a bolt-in swap.  It requires moving the hole in the floor 3" back for the shifter.  It also requires some mods to the rear-trans-cross-member to fit the 5 speed rear-mount, OR just use an OEM cross-member from a truck that had a 5 speed OEM.  One slight drawback to the swap.  The W50 has a higher 1st gear then the original 4 speed so it will be a little harder starting in 1st unless you also happen to change the rear-axle ratio.

Note that before I did my first swap, I checked a chart at Marlin Crawler who many regard as the "go to place" for Toyota truck info and performance.  Marlin's chart says no other 5 speed trans will fit the older trucks because it requires a shorter transmission then most newer ones use.  

Now - to my surprise.  I recently picked up a 1988 Toyota truck trans, Aisin model G54.  Marlin says it is too long to fit into a 1978 truck.  Marlin says the 1978 trans is 20.8" and the 1988 trans I have is 25.5" long.  Well, guess what? I just found out, by accident, that the 1988 trans is NOT longer and is actually a better fit into a 1978 truck then the original 5 speed is.  Not only is the G54 exactly the same length as the original four speed, it also has the shifter in the same place.  So, no mods at all if you get a 1978 cross-member for a 5 speed.  Even better, the G54 has a nice low 1st gear. Even lower then the original 4 speed has. Had I known this, I'd never bothered with a W50.  So much for trusting info on Net; even from places like Marlin Crawler.

One added comment.  Somebody recently claimed they could not swap cross-members on their Toyota Chinooks because they were welded in. I just finished a 1978 for a friend.  The cross-member was bolted in with his four-speed. I got a cross-member for a 1978 five-speed truck shipped to me for $55 total.  All went in just fine.

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JD,

Have you done the swap? Do the splines on the G54 mate up with the 20R clutch setup?

It's something I may consider doing.

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Hay jd I would love to put a 5 speed in my 1978 Toyota mh so does the splines the same as the original 4speed have you done it?do you have any information the swap?

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17 hours ago, fred heath said:

JD,

Have you done the swap? Do the splines on the G54 mate up with the 20R clutch setup?

It's something I may consider doing.

I have three transmissions here that I've checked over and/or installed into Chinooks.   One is the four speed I've yanked out of 1977 and 1978 Chinooks.  Called an L42 or L43 as I recall.   Then there is the optional OEM five speed that was offered in 1977 and 1978.  That is the model W50.   Then there is this 1988 transmission I just got. Model G54 five-speed.

All three transmissions are exactly the same length.
All three transmissions have the same input shaft splines and use the same clutch disk.
All three transmissions have the same output shaft splines.  I.e. a 1977 Chinook yoke fits the 1988 five-speed
All three transmissions have the clutch linkage, slave cylinder, etc. in the same place with same bolt pattern.

The 1977-78 four-speeds and the 1988 five-speed (G54) have the shifter in exactly the same place. The 1978 W50 five-speed is around 3" back further.

1977-78 four-speeds and 1988 five-speed (G54) have the speedo-cable hookup on pass. side.  1978 W50 five-speed on driver's side.

Rear crossmember and rear trans mount.  This requires change if swapping any 5 speed into a 77-78 that originally has a four-speed. you either have to modify your existing mount or just get the correct crossmember.  Note - at the Yahoo Toyota Chinook forum - one guy claimed his crossmember was welded in and not removable and he spent hundreds of dollars modifying the mount.  I'm not sure what to say but this. I've done two so far.  A 1977 and a 1978 and both had crossmembers that bolted in.   I just bought a 1978 crossmember out of a 5 speed truck last week for $35, plus $20  shipping.  I have also modified one of these and it took me less then an hour.  Certainly not "hundreds of dollars"  in work.

Note that the OEM five-speed used in the 70s trucks has a higher first gear then the four-speed.  Four-speed is 3.67 to 1, and W50 five-speed is 3.28 to 1.
The 1988 G54 five-speed has a nice low gear of 3.92 to 1.

 

W50 five speed  1975-79 (used in trucks) 21 spline output

 Came in 73-81 Celilca, Corona, Supra, and 76-82 Hilux trucks

1st gear is 3.28 to 1 ratio

 

L42 and 43 four speed  1976-80  3.67 to 1 1st gear,  21 spline output

 

L45  1981-82  four speed 3.92 to 1 1st gear,  21 spline output

 

L50  1981-82five speed     3.92 to 1 1st gear,  21 spline output

 

L52  198 five speed   3.92 to 1 1st gear,  21 spline output


G52  1984-86   3.92 to 1 1st gear,  21 spline output

 


G54  1986-88    3.92 to 1 1st gear,  21 spline output
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Mines the L43, and the cross member just bolts on.

Sounds like it should work. Thanks for the research. ?

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The last one I just picked mine up from a junkyard in Canada.  I was in the area anyway and they brought it across the border for me. It was part of a "package deal" to convert my 1988 Minicruiser with a 22RE to standard shift.  So I paid $400 for the trans, bellhousing, clutch, flywheel, clutch pedal assembly, master and slave cylinders, etc.  There are many transmissions for sale at centralized junkyard databases like www.car-part.com    Also note that Toyota transmissions that have removable bell-housings are light enough and small enough to ship via UPS.  I got my 1978 five-speed shipped to me from California and the total price with shipping was around $200.  That was the W50 I put into my 1978 Chinook. It is fine but I also put a 4.56 rear into it at the same time. I suspect I would not like it with the OEM 4.10 rear because of the higher first gear.  If I had known about the newer G54 being a better option, I would of done it. I just found out by accident.

toyota trans ads.jpg

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No, it is already in a Chinook.  Besides - I had some time invested in it. I tore it apart to every last bit and checked it all over.  I could not find anything wrong with it so I did not put in any new parts except seals and gaskets.  I do the same with any used trans unless it has come out of vehicle I get to drive first and check out.

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  • 1 year later...

Hey, Z.
I'm about to yank my 1978 20R out of my RN28L, and replace it with a 22R hybrid. I have an '83 22R out of a RN44L, sitting in front of my Dolphin, with its W52 attached.

My '78 has a G082 and the '83 - 22R / W52 came with a F302 (which I don't have). That, the driveshaft, and the cross member are still at the wreckers.

Have you worked with a W52? My head's dizzy from all the talk of grinding, welding, cross members, axles, gears, and ratios from all the forums, but you've actually been putting these things in and mixing and matching. Does it sound like I'm going to be able to use the W52 for my application?

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Thanks, Linda. Great of you to let me know. If anyone else has knowledge, please weigh in. I'm going to start stripping the 22R for the job, but I'm more than a little confused about the W52. I don't mind the challenge, I just don't want to end up like Sisyphus.

Sisyphus.jpg

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  • 3 months later...

i'm just now about ready to yank my 20R & L43 and put in hybrid and 5 speed.

i bought a 1983 22R with a W52 (Australian 2WD SR5 Extra-Cab ).

Now, i find that the W52 does not have the proper gear ratios, for my 1979 Dolphin and its driving habits.

Plus, the 6 lug axle i bought a while back has a 4:10 rear end.

eBay has Revolution Gear & Axle Toyota 7.5" gears for $170, with a 4:56 ratio. is this a do-able upgrade?

is there a difference in an automatic tranny rear end 4:56 and a manual tranny rear end 4:56?
what vehicle(s) do the 4:56 come out of? is there a website that matches rear ends to vehicle models?
is the L43 out of a 1978 long bed use or fit the same 5 speed cross member as a 1983 SR5?

I can sell the W52, I'm just not into having the wrong gearing for my Dolphin. i'm in it for the long haul ... i put on a lot of miles, on and off road.

thanks for your time, ron alan.

 

 

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24 minutes ago, Ron Alan said:

is there a difference in an automatic tranny rear end 4:56 and a manual tranny rear end 4:56?

The driveshaft length would be a different length I think, but no difference otherwise from an auto vs manual in fitting the diff.  A used 3rd member/pumpkin should fit right in.

25 minutes ago, Ron Alan said:

what vehicle(s) do the 4:56 come out of?

You might want to use a gear calculator to see if the 4.56 is really the best fit for you.  You might find something else that's even better.
I've put some used gear ID info in a PDF file. These should all be 8" diffs that would fit the dually axle. I haven't tried to post a PDF file here before so someone let me know if it doesn't work:   Used Gear ID toyota rear.pdf

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The W52 is pretty unique. [Applications (calendar years): 1984–1988 2WD Hilux (AU)]. I've calculated speed with few different diffs for you.  All are at 3200 rpm and give you the speed in mph at that rpm.  Each image is a different diff ratio.

Do you have 185R14 tires?  These calcs will change with tire diameter, I've used 24.4 inches which seems to correspond to a loaded 185R14 pretty well.  I can re-do the calcs if you tell me your correct tire size.

The 4.56:

244506199_W523200rpm185r144p56.JPG.43c00f71ff364c7bea1661f56c524470.JPG

For a 4.1:

152125829_W523200rpm185r14.JPG.bd4d6713dd0788c3d52b46dfe5530494.JPG

I'd double check my calcs to make sure I didn't make any errors but it seems like the 4.1 would do just fine-- at least to get everything going and test it you might not want to go through the trouble of finding a different diff. It depends on what RPM and speed you want to run when you hit 4th (1:1) or 5th (.853:1) gear.  There is no "right" gear, it's just a matter if figuring out what gear fits your driving style and hill climbing needs.  the 4.56 would do climbing better and if you don't mind running RPM high at like 3500 then you can hit 55 mph in 4th and 65 mph in 5th.  Your speed with 4.56 would be about 71 mph in 5th at 3800.  You may find that you like running at a little lower RPM with the 4.1 you already have to get some decent speed.  If you don't have big hills to climb then you might be set with the 4.1.

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19 minutes ago, AtlantaCamper said:

gear calculator

AtlantaCamper,

wow. great pdf file on used diff's.

i never heard of a gear calculator, the on-line ones i found were based on rpm and tire/wheel size.

i run les schwab 185R-14-8 thunderer. they're right at 25". i was told the 8 ply makes them taller.

mine's an 83 and i'm no where near australia.

i just don't want to end up winding out first gear and so on..

thx, agin.

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23 minutes ago, AtlantaCamper said:

24.4 inches

does the 25" tire height throw off your calculations?

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I found that list of diffs because I'm looking to try a 4.88 in my axle.

The online calculators are the same as what I'm using, mine is just in a local excel spreadsheet.

I'm using the same Thunderer tires as you.  They are 25" without a load but a little shorter loaded.  Half an inch doesn't change the calcs in any meaningful way (2.4%). 

I see your point about the low gears.  First and second are geared pretty low.  I'm short on any additional experience here but let me know if you want any additional calculations done.

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thanks for your help.

its the tranny that i'm most concerned about, the diff can be dealt with later (after testing)

i'd rather put the action on pause if there's a tranny problem. i don't want a whiner.

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2 hours ago, Bsunrader said:

Fred did you switch  the l43 to w58?

No. I like the L43. I have no personal knowledge of this swap but a former member of this forum who’s done the swap claims it’s an almost perfect swap. Splines, shifter location all match up with the L43. This member was an authority on the early chinooks. In fact, the L43 currently in my rig I obtained from him. 

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