zz_denis

Hi guys,
I've been lurking on these forums for a long time, but recently ran into a problem that I could not find a solution for, so I decided to make a thread

I recently replaced auto transmissions on 1999 4runner. I had a good spare tranny from a 1996 parts truck that I used. Externally the transmissions looked identical, so I assumed they were interchangeable. After installation, I found out I was wrong. As I now know, valve bodies were significantly different on 1996-1998, 1999-2000, and 2000-2002 3rd gens.
(as I found out from this thread):
https://www.yotatech.com/forums/f2/t...l#post51822211

Everything bolted up 100%, all wiring connections are the same.. but the truck basically goes forward in all gears (except park), and requires significant throttle (about 30%) to do so. It feels like the handbrake is on. I didn't try going fast enough to check if tranny would shift, but it doesn't really matter, since there are obviously major problems with the tranny regardless.

My question is this. Is it possible to make this tranny work somehow? I searched for days and could not find an answer. I cant imagine the trannies being that much different. It almost feels like there is a small electrical issue preventing the tranny from working properly. Perhaps a different sensor output that ECU doesn't understand, or something similar.
If anyone has any ideas, or can point me in the right direction, I'd really appreciate it!

Texas_Ace

More then likely the wiring to the tranny was changed and thus the correct solenoids are not being activated.

Did your OEM trans have a kickdown cable?

Barring a bad trans the only real possible cause would be wiring. Pretty sure all the kickdown cable trans missions had the same number of noids, thus it is just a matter of figuring out how to get the correct ones to fire.

Also check the fluid level, if the fluid is too low it will cause the trans to drag. You generally need to add a few quarts after driving it a bit due to the converter filling up.

zz_denis

Thanks for the reply, TA!

Yes, the transmission I installed had a kickdown cable. Like I said, externally the transmissions are identical and everything (wiring connectors, k/d cable, linkage, etc) hooked up to the exact same places.

All electrical connections had the same number of wires...

The transmission in question is good, I pulled it from a running truck and it worked perfect.

Fluid level is also good.

What's the best way to go about troubleshooting the problem further?
Or should I just give up and look for another transmission?

Texas_Ace

Only thing you can really do is track down the wiring diagrams for both models and see how they compare. My local dealer had the BGB with this info you might try them.

zz_denis

Thanks again for the reply.
I did some further research on my symptoms and im starting to have doubts that the issue is electrical.

I did remove the valve body from this transmission when it was out of the truck (long story). I did put it back together, but I suppose its possible (although not likely) that I put it together wrong somehow?

I found a couple of threads on LS1Tech forums describing very similar symptoms, and it turned out that it was caused by manual valve (on the valve body) not being connected properly to the "rooster comb" after valve body installation. I will try to remove the pan tomorrow and check.

Texas_Ace

A small leak anyplace on the valve body mating surface could easily cause these issues. Or if anything else was not dealt with properly.

zz_denis

I dropped the tranny pan today and noticed right away that the "stub" on the rooster gear was not aligned with manual valve on the valve body.
I lowered the valve body slightly (didn't have to remove it completely, which kept things from falling out from above the VB), aligned the manual valve properly and put it all back together.
Transmission now works great!
It shifts good, doesn't drag, etc. Multimode transfer case also works fine with it.

The only issue is that I managed to overtighten and strip the threads on the VB for one (of 4) of the oil filter mounting bolts. Hopefully it wont cause any problems.

So I guess its a confirmation that although significantly different inside, 96-98 trannies will bolt up and work fine in 99-00 trucks.

Texas_Ace

Not sure about 00 trucks as mine is an 00 and the electrical connections were most certainly different between them.

Glad you got it working!