Auto tranny shifting issue

[03lances]

Hey guys new here with a question. My buddy has a 1995 pathfinder, he made the unfortunate mistake of hooking it with a tow bar behind his F-250 to tow it without removing the driveline. He only went a couple blocks before the tranny started smoking. Wierd thing was he only blew out reverse. all the forward gears work fine. So we found a tranny for it 2 hours away. Even used the pathfinder to go pick up the transmission. Swapped it out but the problem is if you just try to get in it when cold and go it wont shift. It will rev out to 6k and only way to get it to shift is to let off the gas then it will shift, then continue to accelerate it will rev out again until you let off the throttle and then it will shift. As you drive it for 10-15 mins it will get better and better shifting until its fine... until the next morning when it happens again and again. I found if you start it cold and put it in neutral for 5 mins or so then leave it shifts fine right off. Any ideas? Fluid is new.

[smj999smj]

Those are usually classic symptoms of hardened piston seals inside the clutch drums. When the fluid is cold, the seals are hard and won't seal well, thus the trans slips or won't even engage. As the fluid heats up, it warms the seals and they become more pliable and start to seal. So, bottom line is that you have a bad transmission. In order to replace those seals, the trans has to be completely torn down and overhauled.

[03lances]

So when you say slips you mean it wont shift correctly? The tranny engages just fine and does not slip in terms of revving out without gaining speed, if you mash the gas cold or warm it grabs and goes just doesnt like to shift when cold.

Thanks for the reply man just want to confirm the above is what you mean.

[smj999smj]

Note the word "or" between "slips" and "won't even engage." Symptoms depend on how bad the seals are and can also include delayed engagement. You can always do a line pressure test to confirm, but I think the inevitable is that the trans needs to come back out and repaired or replaced. Due to the age, I wouldn't trust a used trans for a WD21. Your best bet is to have the trans overhauled or get a reman replacement. Those trannies are too much of a pain to be taking in and out until you find a good one!

[03lances]

Gotcha. Yeah it was a pita on some parts especially those damn converter bolts. Good idea with the line pressure I had a feeling it had something to do with the fluid pressure.

[03lances]

So can you tell me where to find the plug to tap into the mainline and test the transmission fluid pressure? Also If I get this kit will I need an adapter?

http://www.amazon.com/OTC-5610-Transmis ... ure+tester

Sorry for all the noobish questions I really am not a noob lol. I do mechanic work all the time just I usually dont try to diagnose transmissions I just replace them if there having issues.

[03lances]

K nvm on location of the pressure port I found that, and damn amazon doesnt have that kit in stock its a couple months out grrr. Anybody have any suggestions on a descent kit comparable to this OTC one? I like OTC brand I have a timing kit for the 4.0 sohc ford engine that is built tough and very specific.

[03lances]

Update:

He threw seafoam in the transmission the other day and now when it is cold it starts out in second gear, bogs hard getting going. Once the tranny warms up a bit it resumes normal shifting. What might that indicate guys? Would bad solenoids cause this? Or are we still thinking its the seals inside the clutch drums? Thanks

[smj999smj]

The Seafoam softens the seals, which is why it's working a little better. Don't waste your $ on the trans pressure gauge unless you plan on doing a lot of tranny testing in the future. Your trans is bad and needs to be replaced or overhauled.

[03lances]

Thanks I kinda figured thats what it did, any idea why it would cause it to start in 2nd though? Seafoam causing it to be too thick giving it more pressure or something? As far as the pressure gauge goes its a handy tool to have to test oil and tranny fluid pressure and I do several car jobs a week for side work so couldn't hurt to have one lying around

[03lances]

I have been tearing into his original transmission to figure out why his reverse went out. I have it completely disassembled and nothing is obviously damaged EXCEPT the FSM shows this clip on the Brake band that goes around the reverse clutch drum. I could not locate this clip on disassembly would this cause a no reverse situation? I will add his reverse was not completely gone, sometimes it would back up very jerky like but probably 90% of the time it just would not do anything like in neutral.

[smj999smj]

That clip is not a transmission part. It is a clip you fabricate to keep the band in shape after you remove it from the trans. Usually a wire coathanger can be cut and bent into shape to make this clip.