Clunk in Rear End (ZJ)

[Ertsride1]

Hello guys,

I have a 2004 Jeep Grand Cherokee
4.0L, AUTO, NP242(2wd,4ft,4pt,N,4lo)

I have an intermittant clunk in the rear end of the vehicle.

Sometimes it clunks when I release the Brake pedal at a stop light sometimes it rolls 1-5 feet and then clunks.... it almost feels like someone hits the back of the vehicle...

I have replaced all the brakes and bled eveything...
Rotors, Calipers, Ceramic Pads

What else could it be?

I Jacked it up by the rear differential... both rear tires off the ground and spun one tire about 1-2 lugs before the xfer case took up the slack...

the other tire and the drive shaft both spun with very minimal slack...so rear end and u joints are tight...in theory

Any help will be greatly appreciated...

Thanks,
Garrett

[Ertsride1]

I know that this xfer case has a viscious coupler.... is that the reason it has so much movement before it stops...

[xcm]

your might get better help on that viscous coupler on a grand cherokee forum, but i know there are some here with grands...

could it be your driveshaft u-joint? if this was an xj cherokee, that would be my first guess.... but i have heard of that viscous coupler in grands. cant say for sure.

you could pull the rear driveshaft, or just check it by hand. there shouldnt be any slop in the ujoints.

[Ertsride1]

I have it posted it there also... I will check it out later at the house and see what I come up with...

[windle27]

it sounds silly but did you check the exhaust cause my cherokee is missing the the rear hanger and it makes a clunking noise to untill i made a hanger of my own. just something to look at good luck

[Ertsride1]

It sounds like a heavy clunk but will check it out thanks

[rocknxj]

I observed an XJ with the same clunking noise just last night. When moving from Park (or neutral) to Drive, the rear driveshaft rotated an 1/8th of a turn before it engaged, making the clanking sound you described. If this is not normal, I'll have to figure out why it has started doing that.

[RCP Phx]

The 242 t-case doesnt have a viscous diff.

[Ben_Dyer]

if all else fails i would check your backlash. mine was also making that noise and ended up being that the bolts that hold the ring to the carrier were loose and in the end it was not a pretty sight.

[Ertsride1]

If it does not have the coupler how does it allow the full time 4wd on the street... Does it have clutch packs or what...???

[joe_peters]

If it does not have the coupler how does it allow the full time 4wd on the street... Does it have clutch packs or what...???

the 242 is mechanical like a differential, the 249 and others are viscous.

[joe_peters]

if all else fails i would check your backlash. mine was also making that noise and ended up being that the bolts that hold the ring to the carrier were loose and in the end it was not a pretty sight.

My 66 Mustang had this issue, and I really meant to fix it some day, ended up selling it after 30k miles with that nasty sounding clunk--sold it and never did fix it. You could drop the DS at the yoke and make it clunk by turning the yoke--more than a 1/4".

[Screech]

have you checked the ball joint at the rear differental? that could make that kind of noise

[RCP Phx]

have you checked the ball joint at the rear differental? that could make that kind of noise

No such animal,WTF are you talking about?

[Screech]

Im pretty sure theres a ball joint type thing where the rear upper control arms meet at the diff.

[JJacobs]

No such animal,WTF are you talking about?

No joke, is he a salesman for Kaleco Auto?

Again, this is NOT a ZJ forum. It could be a dry slip yoke in the rear driveshaft making the noise.

[kastein]

Im pretty sure theres a ball joint type thing where the rear upper control arms meet at the diff.
You're thinking of a WJ and possibly a WK. The ZJ has a 4 link rear.

[heyhar]

The WJ ('99-'04) has what amounts to a control arm on the top of the diff, and it indeed has a ball joint, and they do go bad. This one arm replaced the two upper control arms and the Panhard (track) bar. The clunk is axle wrap, caused by the axle rotating in the direction of the wheels when braking. Take your foot off the pedal, and it relaxes to its proper position.

[Screech]

The WJ ('99-'04) has what amounts to a control arm on the top of the diff, and it indeed has a ball joint, and they do go bad. This one arm replaced the two upper control arms and the Panhard (track) bar. The clunk is axle wrap, caused by the axle rotating in the direction of the wheels when braking. Take your foot off the pedal, and it relaxes to its proper position.

So I guess im not crazy after all

[heyhar]

What's confusing is you're calling it a ZJ. It's not, it's a WJ, if it's a 2004. I'll guess most folks here are unfamiliar with the WJ, and since your title said ZJ, that's the reason no one knows of the ball joint. The only reason I know is because a co-worker just went through this with his 2000.

[kastein]

Yeah. I've worked on WJs and ZJs a little, so I know the differences, just confused me because the OP titled this thread as if it was a ZJ while it is actually a WJ.

So yes, there is a balljoint thingy on top of the rear diff housing. It's for the upper wishbone/Y/whatever-link they use.