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AW4/Driveline thump when starting or stopping

X

X-defector

NAXJA Forum User
Location
Parker CO
Hey fellas,

My AW4 - at least, I think it's my AW4 although it may be another part of the driveline - is making a funky noise. It makes a muted thump in the driveline that I can feel in the cabin.

The weird part is that there is no consistency to when it happens. Sometimes it happens right before I come to a complete stop...sometimes it happens right after I stop....sometimes it happens when I begin to accelerate...sometimes it doesn't happen at all. It's pretty minor, just a little 'whump' and then we're off to the races. Feels and sounds like it's coming from under the tranny tunnel.

Any idea what this might be? Thanks in advance...
 
Always post your Cherokee info in your threads. Year, engine, trans, T-case, axle type, lift size. The correct answer to many common issues will vary depending on your model year and optional or add on equipment.

1997-2001, that thump usually means you need to remove the rear drive shaft and put some anti-seize lubricant on the slip yoke at the transfer case.
 
Tim_MN said:
Always post your Cherokee info in your threads. Year, engine, trans, T-case, axle type, lift size. The correct answer to many common issues will vary depending on your model year and optional or add on equipment.

1997-2001, that thump usually means you need to remove the rear drive shaft and put some anti-seize lubricant on the slip yoke at the transfer case.
Click to expand...

ok same issue but for a 93 3 inch lift, aw4, 231, d35 rear. please tell me its that easy for me... haha
 
93mudspitter said:
ok same issue but for a 93 3 inch lift, aw4, 231, d35 rear. please tell me its that easy for me... haha
Click to expand...


Your slip yoke is inside the t-case and is lubricated by the t-case fluid. I would inspect the u-joints, shock bolts, leaf springs and u-bolts in your case.

Some slight drive line clunking should be expected as normal due to age and mileage increasing the tolerances in side the differential and t-case.
 
X-defector said:
Hey fellas,

My AW4 - at least, I think it's my AW4 although it may be another part of the driveline - is making a funky noise. It makes a muted thump in the driveline that I can feel in the cabin.

The weird part is that there is no consistency to when it happens. Sometimes it happens right before I come to a complete stop...sometimes it happens right after I stop....sometimes it happens when I begin to accelerate...sometimes it doesn't happen at all. It's pretty minor, just a little 'whump' and then we're off to the races. Feels and sounds like it's coming from under the tranny tunnel.

Any idea what this might be? Thanks in advance...
Click to expand...

Your slip yoke on the rear driveshaft can make that noise if it is not greased or worn out.
 
Tim_MN said:
Always post your Cherokee info in your threads. Year, engine, trans, T-case, axle type, lift size. The correct answer to many common issues will vary depending on your model year and optional or add on equipment.

1997-2001, that thump usually means you need to remove the rear drive shaft and put some anti-seize lubricant on the slip yoke at the transfer case.
Click to expand...

my thump means that i have a detroit in the rear, and a gearset that has too much backlash. detroit has a lot of backlash built in too, so between the two of them, it goes thunk a lot.

you have any traction aid, or aftermarket gears in the back?
 
I had a thump for a long time in my XJ. I always thought it was the rear driveshaft, but everytime I crawled underneath and tugged on it I couldn't get any play. When I took the rear driveshaft out this past weekend to install my SYE I found that the ujoint at the tcase was missing two caps and all of the bearings. It wouldn't budge by tugging on it, but it was shot. My thump was very inconsistent and would happen from a stop or sometimes when I let off the gas.
 
Tim_MN said:
Your slip yoke is inside the t-case and is lubricated by the t-case fluid. I would inspect the u-joints, shock bolts, leaf springs and u-bolts in your case.

Some slight drive line clunking should be expected as normal due to age and mileage increasing the tolerances in side the differential and t-case.
Click to expand...


Mine does it when im extremely light on the throttle or let off the throttle. it will thump several times like someone is hitting a rubber mallot on the undercarriage. Also get bad vibes when stopping and my left rear drum has been locking up when it raining. im befuttled:dunce:
 
Thanks for all the replies. Guess I should post Jeep info.

'97, 4.0, AW4, NP231, D35 Trac-lok, UpCountry package, 140k - and bone stock (hey, cut me some slack - I just bought it a few weeks ago). :D

I thought of a u-joint but the inconsistency is weird - and it's only one single thump when it occurs, never a series of them.

So what's the story with the slip yoke? I can certainly see how that could be the problem based on the symptoms. But does it need to be lubed/anti-seized or is it really lubed by the T-case fluid? The slip yoke seems like the first place to look...
 
Just adding my experience... 99 and a 96, both have the occasional "clunk" from the rear. When I got my first one in 05 (the 99), I was worried about it, but I've come to accept it just like the wobble in the 55-60mph range. I've talked to quite a few ppl who have mentioned this "clunk" and said that a lot of chryslers do it. Not sure how much truth there is to that, but he was an older guy who seemed like he had some experience.
 
calvynandhobbs said:
I had a thump for a long time in my XJ. I always thought it was the rear driveshaft, but everytime I crawled underneath and tugged on it I couldn't get any play. When I took the rear driveshaft out this past weekend to install my SYE I found that the ujoint at the tcase was missing two caps and all of the bearings. It wouldn't budge by tugging on it, but it was shot. My thump was very inconsistent and would happen from a stop or sometimes when I let off the gas.
Click to expand...

mine does the same thing, when im comming to a stop or starting, and no play in th ds, time to put in new u-joints i think
 
Lube the slip yoke, it takes about 1/2 hour to do. You either already have anti-seize, or you need to buy some.

While the DS is out, inspect the u-joints. If lube doesn't help, suspect the u-joints.
 
I was having a similar issue like this and it ended up being the tranny mount worn out thus the exhaust hanger was rubbing the floor panel whenever I started driving with medium throttle from a standing stop. Replaced the tranny mount with a stock new one and everything is normal know.-

HTH

XJ-PRO
 
things to check that everyone already said that i would do:

-front/rear ds u joints inspect and maybe replace
-control arm bushings
-rear brake shoes for proper adjustment(its done it to me)
-tranny mount
-maybe even leaf bushings...
 
I'm really suspecting u-joints as this morning coming to work went over a bad hump in the road which extended the rear suspension and it made the same noise.... guess I'll be picking up some u-joints after work...
 
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