1988 trans swapping??

[zero]

I'm wondering if anyone here had tried swapping their A43D trans for something else?   I've had it with the A43D in my 1988 Minicruiser.  It has worked flawless; no problem there. I just do not like the power and fuel-mileage loss that comes with it.  I am seriously considering converting it to a 5 speed manual trans with the 4.56 rear.   I have a chance to buy a complete, good running 1991 Toyota pickup with a 22RE and 5 speed trans for $400.  Seems it would have all the parts I need for a swap.  But - I've also wondered about the possibility of putting in a A43D with lockup, like from a 1991 Tacoma.

[Allen]

Hi JD,

Sorry this response is not that timely; however, I just got back from being out of the country on a business trip for 2 weeks.

Anyway, there have been at least a couple of us who have converted their automatic transmission to 5 speeds, either by having the work done for them or doing the work ourselves.  Please see my previous posts and links on this topic (http://toyotamotorhome.org/forums/index.php?/topic/4347-how-many-miles-does-your-dolphin-have/#comment-25019).

For almost 22K miles, I was running the previous 4:10 rearend.  I recently upgraded to a 94 4Runner 4.56 ratio pumpkin with an Eaton TrueTrac, since almost getting stuck getting out of Monument Valley’s 17 mile scenic drive and almost burning up my clutch trying to get out.  I cannot really say anything about the mileage yet (only about 250 miles); however starting out now is much easier!

In regards to being able to pick up a 91 for $400, that is a great price!  You might still have to pick up some parts, since there was a body change between 88 and 89.  I am not sure if the pedal assemblies are the same, along with the cross member bracket; however, you will have a great start from the 91.

Regards,
Allen
 

[zero]

Thanks for the reply.  I hope to hear what sort of gains you got with a manual trans swap and some overdrive.  I already have a 4.56 rear in mine I put in last year with new Yukon gears. I've just had it with the auto trans although it HAS worked flawlessly.  Any auto trans with no lock-up converter is a slipping oil-heater and power robber.  Even with lock-up, it still steals engine power to make hydraulic pressure.

[Donnie]

Maris, I'm probably the last person that you want to hear from, but anyway:  you have already completed the most logical  part by installing a 4;56 rear.  That is Good, but your converter was designed with a higher stall to accommodate your 4;10 rear... you could have a converter built a bit tighter, to lower your stall speed thus allowing you to throttle less to be moving & you would feel less converter slip.  You already know that a lock up clutch in your converter is mostly useless as the slightest vacuum drop or TPS movement will unlock it.. I'm sure that with your capability you would be able to keep it locked longer than the factory programming which may be an advantage for you.. Something to consider... Milt at Precision should be able to help you or a few other converter builders are out there.......  my shop is closed now, but I still belong to the group.. any other referrals needed, please comment..good luck..................donnie

[zero]

3 hours ago, Donnie said:

 your converter was designed with a higher stall to accommodate your 4;10 rear...

  You already know that a lock up clutch in your converter is mostly useless as the slightest vacuum drop or TPS movement will unlock it.. please comment..good luck..................donnie

As far as I can tell, Toyota never designed (or ordered) any trans or converter with an overloaded RV in mind that just about never got driven with overdrive engaged.  Subsequently, I don't see what the 4.10 ratio has to do with any stall-speed design.  Toyota built a truck with a 4.10 rear and an overdrive of .688. Not a truck with a 4.10 rear driven all the time with a 1 to 1 ratio in the trans.   So - when changing gears to 4.56 and then being able to use the .688 overdrive - not really a huge change for demand on the torque-converter as I see it.

As far as lock-up goes with a conversion?  At this point, I am kind of clueless when it comes to a A43D with lock-up. I just assume there are easy work-arounds. Last automatic trans I rebuilt was a 700R4 in a diesel Chevy Suburban and it was easy to modify it so I had lock-up in 2nd, 3rd, and 4th.     My 1994 Ford diesel with an E40D, in stock trim, has lock-up in 2nd, 3rd, and 4th.  In fact, it has too much due to some sort of problem.  When cold, once it reaches lock-up, it stays locked up.  Almost pushed me through a red light once.  Once driven a few miles after a cold start it is fine. Could be a solenoid, could be a mechanical defect in the converter - who knows at this point?  

I'd rather just swap to a 5 speed manual trans, but was considering a lock-up automatic if I found anyone who has done it and is happy with it.  Even with lock-up, the trans would still be robbing engine power to run the hydraulics.  I don't have much of a reference point on the matter. Only thing close is to compare Winnebago Lesharos or Phasars.  I have records of several  with 2.2 gas engines and lock-up converter automatic transmissions.  Most got around 14 MPG on the highway at 55-60 MPH.  No they are not Toyota RVs, but close.  Same size engines (or close), 14" tires, similar wind-resistance and similar GVWR.

[Allen]

We just came back from an 827.7 mile trip from the SF Bay area to Orick* and back.  This was our first major trip with the 4.56 rearend.  We averaged exactly 14.0 mpg.  The individual tanks went from a low of 13.8 to a high of 14.2.  I drove 65-70mph where I could.  Prior to changing the rearend to 4.56, we would average about 13 mpg**.  I think we gained about 1 mpg with the rearend change from 4:10, since the engine is under a lighter load and I am always typically in 5th on the highway now (however time will tell with more trips).  The 5 speed and the 4:56 rearend work well together.  I get more useable power out of the engine now since I can fully use 5th gear, can accelerate better (important for our underpowered motorhomes) and can now start up steep hills.  I am very happy with the 4.56 gear change!

*We visited Mendocino, Westport-Union Landing State Beach, Patrick’s Point State Park, Prairie Creek Redwoods State Park, and Redwoods National Park.
**Six years ago when I did the initial conversion from a 4 speed automatic to a 5 speed manual transmission, my initial conversion mileage was higher.  Over time I used the new found additional usable power with the extra gear and the mileage dropped accordingly.
Note: For reference I am running 195R14 tires on the rear; I upped the tire size shortly after we got the Sunrader to get the speedometer more accurate with the automatic transmission (and they also needed replacing too).  I will be replacing the 185R14 front tires soon with 195R14s too, since they are slightly over 10 years old now.