Any AW4 Tranny experts out there

I have an AW4 in a 1987 Cherokee and I am having a problem with the tranny. We can drive for an hour and have no issues but all of a sudden it acts like it goes into neutral. So we pull over and in a minute or two it drives fine. We can then go another hour without any issues. This has happened three times. The tranny fluid is flushed every 5000 mile do to we really only wheel our Cherokee and it is not a daily driver. I am by no means a tranny guy. I checked the fluid level and it is perfect and clear. Any help would be appreciated.
Thanks

Does it exibit any strange shifting issues before it goes out, like not wanting to down-shift? If so it could be heat related.
I don't think a faulty NSS would cause your symptoms.
Locate and flag the fuse for the TCU(transmission control computer). Next time it happens, pull the fuse and manually shift. You should get 1st, 3rd, and 4th with the TCU disconnected/powered down. If that works, it's a faulty TCU.

Also possibly a partially clogged filter.

After a bunch of research and call a couple of long time Jeep mechanics I believe that we have found the problem. We are thinking that the TPS is going bad. After that I did some online research and found that a few threads that dealt witht the issue and the TPS was the problem. I will update this thread after I change out the TPS to see if it works. It happens so intermitent that we will put some mile on the jeep to make sure that fixes it.

Cruzin Illusion said:

I have an AW4 in a 1987 Cherokee and I am having a problem with the tranny. We can drive for an hour and have no issues but all of a sudden it acts like it goes into neutral. So we pull over and in a minute or two it drives fine. We can then go another hour without any issues. This has happened three times. The tranny fluid is flushed every 5000 mile do to we really only wheel our Cherokee and it is not a daily driver. I am by no means a tranny guy. I checked the fluid level and it is perfect and clear. Any help would be appreciated.
Thanks

Click to expand...

tbburg said:

Does it exibit any strange shifting issues before it goes out, like not wanting to down-shift? If so it could be heat related.
I don't think a faulty NSS would cause your symptoms.
Locate and flag the fuse for the TCU(transmission control computer). Next time it happens, pull the fuse and manually shift. You should get 1st, 3rd, and 4th with the TCU disconnected/powered down. If that works, it's a faulty TCU.

Click to expand...

Listen to this guy. Not definitely a faulty TCU - that's the only thing incorrect here, it could also be faulty shift solenoids.

Get it to fail, unplug the TCU, and measure the resistance from each solenoid wire to ground. The resistance should be from 11 to 15 ohms, if it is not, your solenoids are cooked and are failing when heated above a certain temperature. My bet is that both solenoids are failing open and the transmission is going into overdrive + torque converter is unlocking, which combined feels pretty close to neutral when you're going slow.

Definitely test your way to a solution--money seems to always have so many good places to put it, buying parts you don't need is such a waist.

If you unplug the TCU, as mentioned already, and the symptoms disappear, you have confirmed that the mechanical/hydraulic side of the transmission are good. Other than the basics of fresh, clean fluid and your adjustments, that leaves you with the electrics--TPS, TCU, TCU fuse, solenoids, harness.

Good luck.