Auto 4 speed to 5 speed swap possible ? (1 Viewer)

[ceejay LC100]

Hi all,

I have a 1998 100 V8 with the A442F 4 speed auto box.

I have been having endless trouble with very harsh shifts on this box and was wondering if it would be possible to retro fit the A750 5 speed box from a later 100 into mine.

I know the boxes are computer controlled so my concern is how does one transfer the electronics from the donor car to mine ?

 

[Sandroad]

From looking at the electrical wiring diagram over the years for other things, I'd venture to say that is not possible. The transmission ECU is too integrated with all the other control systems and sensors. I'd get the 4 speed working right or replace it with another 4 speed.

 

[ceejay LC100]

Considering, I will be taking the 5 speed box out of a later 100 series which uses the same engine, isn't there some swap I can do... may be with wire looms and control units etc to retrofit the 5 speed into my currently 4 speed 100 ?

 

[2000UZJ]

I'm sure it's possible. Nobody has done this swap on here. My best guess is the ECU needs to be swapped, the main transmission harness needs to be swapped, the interior shifter gate, etc. The t-case is the same, so that is probably a direct swap.

I would compare the 5spd plugs and wiring to your 4spd. A EWD for both years should clearly show you the differences. Toyota harnesses are NOT cheap, take as much as you can out of the newer truck.

 

[TXLX100]

I've never heard of this being done. I would start checking all pertinent drive train part numbers in the old truck with the donor truck. Components like the ECUs and harnesses, as previously mentioned. Also a consideration is the VSC, how integrated is it in the donor truck? I don't think it anywhere near an easy swap, but cheers if you find a way.

 

[spressomon]

Hi all,

I have a 1998 100 V8 with the A442F 4 speed auto box.

I have been having endless trouble with very harsh shifts on this box and was wondering if it would be possible to retro fit the A750 5 speed box from a later 100 into mine.

I know the boxes are computer controlled so my concern is how does one transfer the electronics from the donor car to mine ?

Where are you located where you have an A442F in your '98 100?! I'm unaware of any pre '03 100's that didn't come with the A343F AT variant...at least in North America.

I know Slee and crew looked at a A343F to A750F conversion...so did Wholesale Automatic Transmissions. And I think the end result was too complicated/expensive to get it backward compatible assuming it could be done at all.

 

[Muddy Bean]

Ok, so my tranny is failing. Not sure how much time I have left, but this year has been epic. Broken front diff, and trans failure. So, how hard is a manual tranny swap into a '98? Easier than a 5speed auto swap? Also, looking for recommendations on where to buy a replacement 4spd?

 

[spressomon]

I think you'll have a similar problem: You'll need to figure out how to fool the ECU(s).

 

[yotasavg]

I keep thinking, mini truck guys do this all the time with the 1UZ (tricking the ecu for a manual)... so there must be a way...

 

[FlammableFishie]

It'd be pretty cool to figure out how to swap in a manual for when the A343F inevitably fails. I've always wanted a manual tranny in my hundy.

 

[Muddy Bean]

finding out how hard it is to find an a343f....even remotely cheap. Don't really want a used one...would rather reman. but after our upcoming $2100 front diff bill, I'm counting the pennies.

 

[spressomon]

Muddy...sorry if you have an existing thread on this: Have you/the AT shop determined the cause of failure?

 

[Muddy Bean]

Spress...sent you a PM