AW-4 Transmission Issues

I need someone to confirm my diags and point me toward possible problems spots:

• 1996 AW-4 with 182,500ish miles
• Tranny has seen occasional service over the latter half of it's life, no clue what the previous half was like.
• Fluid is full and red, tested as directed while hot and in 'N'
• Has been vibrating the last few months but has been getting progressively worse; vibrations are definitely engine RPM related and not related to road speed (I can upshift and the vibes become less harsh)
• Only one of four mounting bolts under the inspection cover was loose - that has been retightened along with the other three
• VERY rough idle at startup (began that trick this afternoon)
• While starting from a stop, I now have a low-pitched rumbling that feels like ...a low pitched rumbling. It's hard to describe right now, sort of like a 5-speed does when the clutch is dying and slipping. It continues to vibrate madly at all speeds however.

Once the engine cools sufficiently, I will double-check the bolts and flexplate to rule out a cracked flexplate.

Any thoughts??

Sounds like maybe the flexplate is loose from the tranny. Had that happen to a guys XJ on the trail, we thought it was the motor and it was going to throw a rod, it was that loud.

yep, I would check the flexplate. it may be loose or cracked. a new one should be $50-60

Gonna kinda hijack this thread for a bit cause I know everyone will read it...


I have a 94ZJ which has a strange tranny prob. When the vehicle and tranny is cold and I put it in drive it will not go right away - it sort of "slips" but picks itself up right away after the rpms get high enough; it will move but very slowly for a few seconds and then its fine. Once the vehicle warms up it won't happen.

I have had the tranny flushed by a professsional shop if that helps.

I have that "puke-joe" tranny I think if that helps.


Thanks for readin and respondin!

P.S.

I hope you get your problem worked out Yucca.....


JC95

jeepcherokee95 said:

Gonna kinda hijack this thread for a bit cause I know everyone will read it...


I have a 94ZJ which has a strange tranny prob. When the vehicle and tranny is cold and I put it in drive it will not go right away - it sort of "slips" but picks itself up right away after the rpms get high enough; it will move but very slowly for a few seconds and then its fine. Once the vehicle warms up it won't happen.

I have had the tranny flushed by a professsional shop if that helps.

I have that "puke-joe" tranny I think if that helps.


Thanks for readin and respondin!

P.S.

I hope you get your problem worked out Yucca.....


JC95

Click to expand...

How kind of you, and ZJ's never used Puegot trannies.

I almost forgot Yucca there. The flexplate will definitely make noise if loose or cracked. But it isn't usually accompanied by bad vibration if thats all thats wrong. If one of the bolts for the torque conv. is missing, that could create some balance issues. Does the vib get progressively worse as rpm rises, or worst at a certain rpm? Is the trans firmly bolted?

I pretty much said F-it today and haven't even looked at the Heep again; but spent the afternoon rearranging some of the mess in the garage in case I need it soon.

The crunchy-grindy-bad clutch type sound seems to go away as I get to about 15...or maybe the tires and tranny vibration masks it.

The vibes themselves get progressively worse as I speed up, and (assuming flat road) are pretty wicked by about 40-45 mph...3d gear and whatever rpm that works out to. If I bump it up into OD at that speed, the rpm drops a few hundred and the vibes become much less pronounced. In OD, the vibes get real bad again around 55ish mph and stay that way 'til about 65.

By "bad" my inside rearview mirror looks like a frog in a blender (joecartoon.com) and the outside one has a major jiggle as well...think "Rosie O'Donnell jumping to get a spoon of ice cream" type of a jiggle. Additionally, every loose or semi-loose item in my dash dances around pretty well...

Like I dsaid, I'll fart around with the flexplate as best I can tomorrow. All four bolts were present and tightened last time I was in there.

I had something very similar to what you do and it turned it to be something i never expected . I looked at the flexplate bolts and it turned out to be the tranny bolts that became loose, and i guess allowed some slop. THey were only a slightly loose but that fixed the prob, so take a look at the two side bolts in addition to the flexplate.

pete

One more thing - I didn't see you say anything about vibes in neutral going up or down with engine speed. I know you said it's keyed to engine speed, but you make it sound like you were in gear at the time and I don't know if you tried it sitting still or not...

I'd check the torque converter bolts (which it sounds like you've done,) check the bellhousing bolts, and make sure there aren't any sudden "clean" spots on the periphery of the torque converter or the flexplate where you may have "thrown" a weight - it's rare, but I've seen it something like twice in 25 years...

Failing that it's possible that something in the TC may be coming loose (REALLY rare!) and that would be significant. That's why I wanted to know if you've checked vibration against engine speed in Neutral (or Park - same net result. Try both.)

Do that extra little check - takes about two minutes - and let us know what you find out.

5-90

It vibed like mad this afternoon in park when I first started it, but I didn't put it in Neutral. I actually thought I'd busted a motor mount and checked under the hood expecting to see some major damage there. I'll play around with it tomorrow...thanks.

jeepcherokee95 said:

Gonna kinda hijack this thread for a bit cause I know everyone will read it...


I have a 94ZJ which has a strange tranny prob. When the vehicle and tranny is cold and I put it in drive it will not go right away - it sort of "slips" but picks itself up right away after the rpms get high enough; it will move but very slowly for a few seconds and then its fine. Once the vehicle warms up it won't happen.

I have had the tranny flushed by a professsional shop if that helps.

I have that "puke-joe" tranny I think if that helps.


Thanks for readin and respondin!

P.S.

I hope you get your problem worked out Yucca.....


JC95

Click to expand...

Sounds like low fluid or burnt disks. What's your fluid smell like?

Yucca...look at the routing of the exhaust system and verify it's not in contact somewhere... While under there, inspect the tranny mount as well as the hanger/isolator above the crossmember. In other words, rule out the little/cheap stuff first.

My tailpipe works it's way over to touching my receiver hitch, and if I didn't 'know' that's what's doing it, I'd be thinking "driveline issues" as well. Stopped/idling in gear I get some killer vibes... if run it up to 750 RPM (or put it in neutral or park) they go away. It may get a housecall by Dr Chopsaw once I decide it's time to wake up the neighborhood.

You shoulda said something while you were at ORI the other day.. I'da looked at it for you and at least given you and educated guess

Digger87xj said:

You shoulda said something while you were at ORI the other day.. I'da looked at it for you and at least given you and educated guess

Click to expand...

Thanks for the offer and it was good meeeting you - I was driving the fiancee's Camry though. We're looking for an old ZJ for her though so we'll be a two-Jeep family.

The fluid is full, and actually didn't smell burnt at all, which surprised me. I am kinda bothered by the exhaust routing now that woody mentioned it though. I noticed my downpipe has about 1/16" clearance between it and the back corner of the pan ever since I got my cat and muffler welded on...what's the normal clearance on that area??

As for jeepcherokee95 - if you've got a ZJ you don't have a Peugeot tranny. What engine do you have, or a better decision would be to un-hijack this thread and start your own here or at NAGCA to keep things un-confused.

Yucca-Man said:

The fluid is full, and actually didn't smell burnt at all, which surprised me.

Click to expand...

Arrgghhh...amending that; the fluid at the dipstick didn't smell burned, but draining the pan last night looked less-than-red...and smelt kinda funny. Not 'funny' in a funny way, either. Crap.

I don't feel like searching, but there are just the four bolts holding the bellhousing to the block, right? Two large (18mm? It's been a long day) ones halfway down, just above the inspection cover (which is torn in two, by the way) and the two E12s up top? They were tight, but my lower starter bolt (the 14mm) was loose...I just reinstalled a starter Feb 21 so that is disturbing.

Of course, there's also a friggin' crack in the bellhousing that needs replacement yesterday.

I need to revisit the tranny-bellhousing bolts and tranny-NP231 bolts as well, but they appeared tight yesterday. We'll see what today brings in that department.

jeepcherokee95 said:

I have a 94ZJ which has a strange tranny prob. When the vehicle and tranny is cold and I put it in drive it will not go right away - it sort of "slips" but picks itself up right away after the rpms get high enough; it will move but very slowly for a few seconds and then its fine. Once the vehicle warms up it won't happen.


JC95

Click to expand...

Sounds like the torque converter. BTDT

Sarge

Hmmm...almost five months to the day after the last post I feel I can safely say I fixed this. During most of the summer the Jeep didn't move as I didn't have much time to dig into it. By August I had pulled the rear RE driveshaft and noticed that many of my vibes while underway were gone. I still had pretty noticeable vibrations from the engine though while at a standstill so I knew there was more to it than crappy assembly from REs driveshaft outsourcer.

Many of you saw this pic:


I pulled that out of the Heep last month and although I had an earlier Renix-era AW-4 available I decided to keep my tranny since the body looked intact. I swapped the bellhousings and replaced front and rear seals on the tranny. Along the way I also did a PORC SYE to remove the Hack-n-Tap, and it wasn't until this evening that I had everything buttoned up adn ready to test drive. The idle vibes are kaput. When the engine starts, it simply runs and rumbles through the Flowmaster but most importantly I can look at my mirrors and actually SEE things behind me.

I've got my original front driveshaft in the rear now and at speeds up to 50mph it is a nice, rumble-free ride again. I'll go faster tomorrow once I re-verify that there are no leaks and I have daylight to deal with in the event that there are problems.

I'll hit the driveshaft shop later this week to see if they can verify that the RE driveshaft is out-of-balance. I think at this point that it was the source of many of these headaches, but I assumed the problems must lie elsewhere... It wasn't until I regeared from 3.55 to 4.56 that they got really bad, which makes sense because of the higher RPM needed to go the same speed. Ain't hindsight a mother?

jeepcherokee95 said:

Gonna kinda hijack this thread for a bit cause I know everyone will read it...

I have a 94ZJ which has a strange tranny prob. When the vehicle and tranny is cold and I put it in drive it will not go right away - it sort of "slips" but picks itself up right away after the rpms get high enough; it will move but very slowly for a few seconds and then its fine. Once the vehicle warms up it won't happen.

Click to expand...

I shouldn't be contributing to the hijacking of threads I know but the Torqueflites do this (i.e. the 727 thats in my powerwagon does this) and its considered "normal." The torque converter looses its fluid overnight and it leaks back to the tranny. Since the fluid is not circulated in PARK (hence the warning "Check in HOT IDLE IN NEUTRAL") on the dipstick it will not move the vehicle until the converter pumps up again. Since the fluid does circulate in P, starting in N instead will allow engagement when you put it in D. I don't know if later Chrysler trannies have this problem and you certainly don't have the 727 in a ZJ or a Peugeot which was 5 speed manual BTW. If you still have this issue its food for thought...