Need some AW4 Transmission advise

My Rig is a '96, 4.0, AW4, 4x4 w/247K miles on the clock.

I started to notice what I though was my transmission slipping about 2 months back. So I did a partial fluid change and things were good. However, this past 2 weeks we've had record snowfall in OK and I've been driving around in 4wd more than ever before consistently. Yesterday morning it was -7 degrees (another record) when I got up and drove in to work. My tranny didn't want to shift out of 2nd or 3rd gear... very hit/miss like it wasn't sure what gear to be in. Then I noticed it felt like it was slipping... RPM's climbing but the XJ wasn't going any faster. Made it to work and it was parked in the garage all day. Come out and head home and able to get on the highway and finally drive ~ 60 mph (had the snow cleared) ... picked up my son and headed home. On the way home the transmission was slipping really bad. As I pulled into my housing edition I was running about 2500 rpms and was basically coasting down the road... ~ 3 mph. Pulled in my driveway and popped the hood. Smoke coming f/the firewall area up f/the transmission tunnel.

Checked the fluid and it was still red, but smelled really burnt. It was also about a qt overfilled it appeared. So I drained some fluid... added about 12 oz of Lucas Transmission treatment/stop slip and then drove it around the block. Seemed to shift ok, but it was also still not fully warm. Parked it and then about 3 hours later tried to drive it on an errand to check the tranny. Got about 2 miles down the road and she started slipping bad again. Made it back home and parked it.

My plan today was to try and do a partial transmission fluid change to see if that helps and add in the other 12 oz of Lucas treatment. Do you think that's a waste of time?

My throttle cable is adjusted properly. My Throttle Position Sensor should be good... but I've had that go out before and it was a way different set of problems then the slipping transmission. Replaced the Crank Position Sensor ~ 18 months back so that hopefully is still good. My XJ starts and runs just fine... except for all the slipping.

Where do I shop for a new/used AW4? I've never had to deal w/an auto tranny before. Should I buy new f/someone online? Not sure where to go on this one and could use help f/those of you who've done this before.

You should pull out the digital MMeter and do some testing first. The AW4 is run by a computer, TCU, that is under the passenger side dash (not sure about 96 year?), and there are 3 electric solenoids that control gear shifts. Disconnect the TCU, or it's fuse, and try using 1-2, 3 and D to shift up and down. If that solves the problem, you have an electrical problem, not an AW4 mechanical problem. Search here for old threads on testing the solenoids and TCU, and wiring. Also, drain and replace the fluid in 3 quart batches, like once a day or week, 3 times (9 quarts net), and see if that does not help as well. Use dexron III.

Do a search for "driving my aw4 like a stick" I had an issue and joe peters put a link up for testing, very helpful. I ended up replacing my shift solnoids. My 1-2 was out so tranny would start in OD and slip like crazy. Just replaced all three while I was in there. Transmissionparts.com was cheapest. $135 and change. The aw4 is a toyota tranny aka. a340 I believe. My rig is a 96 also.

Smoking and burnt smelling tranny fluid really doesn't sound like a solenoid problem.

If the tranny starts in overdrive he's slipping the tranny. I know, my tranny temp gauge shot up when my solenoid went out. Didn't take long to heat up two or three stop lights before I noticed a problem.

Following up on this one:

My transmission runs and shifts fine until it gets hot. 1-3 and OD all as they should. Once it warms up it starts slipping like crazy. Engine revving up but no accelerating. With 247K miles on the Original AW4 guess it's time to replace. Found a used one w/a guarantee for $250. Having a very reputable shop install it for $350 + $100 (for new Torque Converter) w/about a 3 day turnaround. Total of $700 (hopefully out the door).

Going to sell this '96 to my son as I was able to pick up a 'new' 2001 over the weekend w/only 111K miles on the clock. Keeping the '96 in the family, but now have a nicer daily driver for myself.

Thanks again for the advise.

Don't pay to have it done! If you can do the tranny flush and fill, you can do the solenoid swap http://www.naxja.org/forum/showthread.php?t=987463

My 98 is doing the same thing, only it's coupled w/erratic idling at times, and cranks and no starts when warm. I got code P0758 solenoid b, but am also finding out it could be a bad tps, or tcm.. Any thoughts on this guys?

djlarroc said:

Don't pay to have it done! If you can do the tranny flush and fill, you can do the solenoid swap http://www.naxja.org/forum/showthread.php?t=987463

My 98 is doing the same thing, only it's coupled w/erratic idling at times, and cranks and no starts when warm. I got code P0758 solenoid b, but am also finding out it could be a bad tps, or tcm.. Any thoughts on this guys?

Click to expand...

Not a solenoid swap... an AW4 total transmission swap. I simply don't have the time or space to do it myself.

That's cool. Just sayin if you could drain and fill tranny, you can do solenoid swap. That write up shows it's not hard, and the only space you need is laying under the jeep.

I pulled the code for solenoid b on my jeep. Was going to order the pack for $100 (or you can get them from JY), but don't want to spend $100 if it's a bad TPS. Going to check the TPS today and go from there.

Thanks. That is a great link and write-up. I'm sure I will need it sooner or later... ha.

My engine is not throwing any codes. I think after 247K miles my OE AW4 is finally giving up and in need of a refresh!!

djlarroc said:

I got code P0758 solenoid b, but am also finding out it could be a bad tps, or tcm.. Any thoughts on this guys?

Click to expand...

The solenoid code pops up if the tranny thinks the solenoid is bad. Meaning it's either drawing too much current (shorted), not enough (high resistance or broken wire), and that the tranny appears to be in the wrong gear compared to what solenoids the TCU is activating.

A bad TPS is very common as they do wear out and often get contaminated by a zealous owner powerwashing the engine. They can cause bad or no shifting, but they shouldn't be able to cause a solenoid code themselves. Bad TCUs are rare enough that they should be the last thing suspected, although they are easy enough to swap out.

What was the resistance measurements of your solenoids? http://www.transonline.com/transdigest/magazines/1997-10/Shift Pointers/index.html That's usually the dead giveaway that it's a bad solenoid or possibly a wiring problem to the solenoid.

Thanks. Ok.. So with the engine running, I pulled the tps and the idle got much better. So hopefully that is the cure to the erratic idling. And as far as the codes, good to hear it's most likely the solenoid then, and not a bunch of other possibilities. I'll get them replaced next and go from there. Btw, how do I ohm test the solenoids? I can go buy a meter from walmart, but how do I test them?

Have a look at http://www.transonline.com/transdigest/magazines/1997-10/Shift%20Pointers/index.html. http://www.ladyada.net/learn/multimeter/ is a nice little tutorial as well.

I've read the tutorial before, and I see it says to check the tcu. I'm going to buy a meter tomorrow and test the tcu, but still don't know how to ohm test the solenoids. If that's the code I'm getting, I'm assuming that's what needs to be changed? Which I did today btw, and no luck.

WOW, sounds like the EXACT same problem i had when we had all this snow (28")!! Mine had all the same symptoms, except mine puked out some fluid from the bell housing area while trying to go up a hill (may have had too much fluid in it). Had her towed home, and once she cooled off, i drove her up my driveway and into the shop and she drove like nothing was wrong. We went ahead and pulled the tranny out to check the front seal. Looked fine. So i might just change out the solenoids too.