Rear end thump

[Purzell]

I have a little bit of a "thump" coming from the rear end which I only notice when I either come to a full stop (not like a gradual slowing stop, but a full stop) and the Jeep settles after stopping. Or I sometimes notice it on take off from a stop. I have read that this is common when the driveshaft splines need lubricating or the u-joints are going bad. I have no transmission or braking issues at all and I never feel this thumping at any other time. I am also wondering if it could be due to the fact that my rear springs are kind of flattened out, not bad but no idea of the age of my suspension components. Anyone have a favorite test for figuring out where this comes from?

By the way it's not very obvious. Most people who have been in the Jeep have not noticed it but I am sensitive to it. Otherwise I am absolutely loving the Jeep.

(1997 XJ with 103,xxx miles)

 

[SWbySWesty]

I had the same problem on my 1996...I spent hundreds of dollars on new components trying to track it down...eventually I gave up. It has sort of gone away; however, it obviously isn't breaking anything over the past 7 years - so I'll just let it do its thing.

 

[DrMoab]

It's totally normal. It's the transmission shifting into first gear. It's usually caused by the rear end being a little loose.

 

[thethinginthewoods]

It's also possible that it could be worn bushings for the leaf springs or maybe your u-bolts are loose allowing slack/gap in the axle housing-to-leaf pack mounts.

 

[BIGdaddy]

A common issue is the bar pins mounts on the upper rear shocks. the bar pins are not pressed into the bushings very firmly. couple that with old bushings and a solid thump from the rear is a symptom.

Also a blown transmission/tcase mount (its rubber) can give a pretty good thump. good thing is, both are fairly easy fixes, but might cost $30-50.00 for bar pin eliminators or stock tcase mount.

check em out, next time you get a chance.

 

[Joe's Toy]

I'm not to familiar with the Jeep's rear end but I'd suggest you give the "lubrication" theory a shot. Tacomas have a common "thump" that is solved by greasing the slip yoke. The thump comes from the slop in the driveshaft when there's no grease to cushion the movement. Just a idea. Give it a shot before you drop any cash.

 

[Joe's Toy]

Double post. 50 min apart???

 

[Purzell]

Thanks guys, I feel a bit more reassured. I'll try the lube theory first and see what happens.

 

[DrMoab]

I should have read this closer before I posted. I thought the thump was as you were slowing down and coming to a stop. Not as you made it or right after.

I retract my statement.

 

[sass3g]

I had this same issue with my jeep recently. It made the same noise under the same conditions. Mine ended up being loose u-bolts. I tightened them up and the noise is gone.