newbie with tranny issue

[scottyrock]

91 xj,4x4,AW-4 tranny. Last week a solemoid so I was told by 2 tranny shops was out. AAMCO replaced all 3 soenoids and it ran fine for a few days. Now the tranny after shifting into 2 it will almost immidietly shift into 3. Sometimes I have OD sometimes I don't.When slowing down to a stop the engine really bogs down unless I put it in N or 1.When I started it the other day it had a really rough idle for a moment then smoother out.AAMCO is telling it is locking up in high gear.Their solution is a reabuild of course. Could all this be from a TPS or torch converter??I really don't think the tranny is shot but I could be wrong.135,000 miles.

 

[BIGSLVRXJ]

91 xj,4x4,AW-4 tranny. Last week a solemoid so I was told by 2 tranny shops was out. AAMCO replaced all 3 soenoids and it ran fine for a few days. Now the tranny after shifting into 2 it will almost immidietly shift into 3. Sometimes I have OD sometimes I don't.When slowing down to a stop the engine really bogs down unless I put it in N or 1.When I started it the other day it had a really rough idle for a moment then smoother out.AAMCO is telling it is locking up in high gear.Their solution is a reabuild of course. Could all this be from a TPS or torch converter??I really don't think the tranny is shot but I could be wrong.135,000 miles.

I will tell you one thing, AAMCO's solution is always a rebuild. About 3 years ago before I knew anything about vehicles, I had my fluid changed by them in my AW4, a week later it was slipping like a sombitch. I took it back to them and they gave me the $1500 news. If I were you I would definitely test the TPS and every other sensor that even remotely could affect shifting. If it turns out your transmission is toast, just get a lower mileage junkyard one. All the way up to a 1996 will work for you. Even if you don't know how to pull them it'd be cheaper to have a junkyard pull one, and someone else to put it in than getting it rebuilt; probably more reliable too. I just reread all of what you said too, your symptoms now also sound like low fluid, you might want to pull the dipstick yourself, maybe AAMCO didn't refill it properly.

 

[scottyrock]

Though I would add that I just talked to AAMCO and they say it is a hydrualic issue inside.Anyone have experience with AAMCO?

 

[BIGSLVRXJ]

Anyone have experience with AAMCO?

In my opinion...they suck

 

[Daddycajun117]

Try A TPS

 

[Timber]

In Toledo, you can get an AW4 for $225 with under 50k miles.

 

[Jim Mesthene]

Anyone have experience with AAMCO?

I'm sure they have some qualified, honest people working for them, but in my 27 years of professional auto repair experience, I haven't run across any yet.

 

[scottmcneal]

DUDE, you asked for help, trust me listen to these guys, they will save your butt some big cash...You can also see if there is any body in your area that can HELP you at your home or at there house..

 

[BIGSLVRXJ]

DUDE, you asked for help, trust me listen to these guys, they will save your butt some big cash...You can also see if there is any body in your area that can HELP you at your home or at there house..

X2! If he was just a little closer to me I'd help him out.

 

[5-90]

Yeah - if I was going to be on my way through there, I'd stop by...

My old man worked for AAMCO doing R&I some years ago - he was incompetent, and seemed to be about the best they had (which was really scary!)

Reports from the field say that the AW4 doesn't take too well to being overhauled - but I did the one in my 1989 Limited about 60K ago without incident. Either I'm a fluke, or I just did something right (it was far from my first slush box overhaul...)

Try to replicate the idle problem in D, and then again in N. If you get the same problem in both ranges, then it is not the transmission, and we need to look at engine management.

As far as "locking up in high gear" - that's what a "lock-up" torque converter is supposed to do - "lock up" in steady-state cruise. There is a mechanical clutch that "locks up" to make the torque converter a direct 1:1 mechanical coupling, rather like the clutch on a manual transmission. This is done for both efficiency (to eliminate the "slip" inherent in the TC) and to reduce heat (because TC operation does generate significant heat.) Lockup should only happen in steady-state cruise in third or fourth gear - on the highway, it would feel like a "fifth gear" to you, sort of a "soft shift" where the tach stops hunting and settles down.

Unfortunately, I've got all my FSMs packed away at the moment, but someone else here may have a 1991 or 1992 to hand that they could dig out and we could do some digging. If you have access to an ohmmeter, nominal solenoid coil resistance is 11-15 ohms (and the FSM could tell you what wires to test for which solenoids. There are three - two to shift and one for TC lockup.)

 

[lawsoncl]

Though I would add that I just talked to AAMCO and they say it is a hydrualic issue inside.Anyone have experience with AAMCO?

Early upshifts are usually not caused by a hydraulic problem. Check or replace the TPS sensor. You can also manually test the tranny by pulling the TCU fuse and verifying that it shifts properly using the shifter (ie {1-2} gives first, etc)

 

[scottyrock]

replaced the TPS today and had no luck. Tranny still has a premature shift,and engine really bogs down after shifting to a higher gear. Checked the fuse and it was good. Even tried the manual test without the fuse and the engine bogged down after shifting to high gears.

 

[UNCC_99XJ]

This might be far fetched, but how does the fluid look? I've seen and heard of way too old and way too burned fluid play monkey with the shifting of transmissions. Not trying to be an a**hole...just trying to start and eliminate the obvious before you spend the big $$$ on something you might not need.

I have to wonder if they really did replace any of those "bad solenoids".

Check engine light on at all?

Edit: Oh, and my thoughts exactly on AAMCO. Had a guy I used to work with take a Dakota there when his tranny started acting up and they actually made it worse!

 

[scottyrock]

Fuid and filter was changed a couple of weeks ago. I have checked it since and it doesn't look or smell burned and the level is ok. Yeah I have thought a thousand times if AAAMCO actually did change the solenoids. I would do it myself but my mechanical skills are well... below average.But I want to learn and am eager to do so.

 

[scottyrock]

Forgot tp add that the engine light is off.

 

[pma4x4]

I got to jump in on this one.

I have a 96 XJ 4.0 AW4. last December mythe tranny went south. I had it rebuilt by a local factory and performance tranny shop in Jan. It got all the fixins of a rebuild plus a new valve body and torque converter. Since then the lockup has always been kinda funny. it would seem to go into lockup a bit earlier then before and you almost had to go WOT to kick it out down a gear or bump the brakes. About a month ago Lockup would on its own just pop out and stay out until i got to my destination and let it sit for a while. I wasnt to sure so i adjusted the kick down cable and it came back. As of last Tuesday it popped out of lockup and has not been seen since, either in 4th or 3rd.

I took it back to the same shop today and it threw no codes nothing. Took it for a test drive and he suspects it could be the break switch. I know that the break switch is what shuts the lockup off, but i dont know if it would just quite while cruising down the highway.

Now.. the other thing is where my problems kinda differ is a few times now it has not wanted to start in "P" so i through it in "N" and it starts up. To me this sounds like a parkneutral safety switch but would this relate to my problems?

Tranny runs around 150 F on the temp gauge. hotter after a while with no lockup. Fluid is a nice red tint with no burnt smell, its topped off and doesnt leak. TPS was tested and replaced in mine actually before the tranny rebuild. Also a new ECU from jeep.

So i got some similar issues i need help with.

 

[lawsoncl]

Sounds like the NSS (the park/neutral switch) needs addressed since it won't start in park. It may just be misadjusted and not need cleaned. This could also prevent it from shifting into 4th or getting the t/c lockup. The symptoms of the switch on the brake pedal are usually it won't lockup - easy enough to test with a meter.

Kickdown cable shouldn't make any difference to when lockup or shifting occurs.

 

[pma4x4]

Sounds like the NSS (the park/neutral switch) needs addressed since it won't start in park. It may just be misadjusted and not need cleaned. This could also prevent it from shifting into 4th or getting the t/c lockup. The symptoms of the switch on the brake pedal are usually it won't lockup - easy enough to test with a meter.

Kickdown cable shouldn't make any difference to when lockup or shifting occurs.

I appriciate the info. I may be starting to loose faith in this tranny shop. the guy said he is going to order and toss in the brake switch. You say that the PNSS could cause the TC NOT to lockup though? mmmmm....

How do i test the breakswitch and is it somewhere under the dash?

 

[lawsoncl]

If it's way out of adjustment, it may be telling the tranny the shifter is in (3) instead of (D). If the switch looks anything like the 89 brake switch, it's a white switch high up on the brake pedal. It can be adjusted as well as removed and cleaned (meaning it doesn't really need replaced).

 

[pma4x4]

If it's way out of adjustment, it may be telling the tranny the shifter is in (3) instead of (D). If the switch looks anything like the 89 brake switch, it's a white switch high up on the brake pedal. It can be adjusted as well as removed and cleaned (meaning it doesn't really need replaced).

What I dont understand is All the diagrams I see with the brake switch have nothing to do with the T/C. Am i missing something? My brake switch is black and has a 6 prong connection. Any more ideas?

Scottyrock,
I'm not trying to hijack this thread i just have some similar shifting issues and this seems to be the best post i have found on this subject.