My Achy Breaky CLUNK!

Alright guys, I purchased an 00' XJ Sport not 4 months ago and I've had a 'clunk' that happens when I shift from Reverse and Park to Drive(even if I pause Neutral)

I figured it had to do with my leaky rear diff cover, so I pulled that and put new fluid in and resealed it. In doing so, I did alleiviate my hard up and down shifting at cruising speeds- that is smooth as butter now. However, I still have the initial issue.

What else, other than motor mounts, could it be?

Thanks!:looser:

I greased my slip yoke and got away with the most annoying clunk I've had. The grease on the splines drys up and wears out..

962door said:

I greased my slip yoke and got away with the most annoying clunk I've had. The grease on the splines drys up and wears out..

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Thanks, I've actually been looking into this recently as well.

What kind of grease should I use? And I think I'm correct in saying that on 96'+ there are 4 bolts on the frontside of the rear diff, pull them and I can get to the gears, right?

Anyone know of a good right up for this? It is to my understand that the gears need to be removed.

helmetface said:

What kind of grease should I use? And I think I'm correct in saying that on 96'+ there are 4 bolts on the frontside of the rear diff, pull them and I can get to the gears, right?

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Any good qualiy wheel bearing grease will work. Leave the differential alone.

helmetface said:

Anyone know of a good right up for this? It is to my understand that the gears need to be removed.

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You don't need to touch "the gears". Leave the differential alone. You need to drop the rear driveshaft. This is done by unbolting the straps or ubolts that hold the rear u-joint to the pinion yoke at the rear end of the driveshaft. The area you need to grease is the front end of the drive shaft where it slides into the transmission (2WD) or transfer case (4WD). I doubt anyone would spend the time doing a write up, because this is so basic.

check for tightness or replace:

tranny mount
U joints front and rear
leaf spring bushings
control arm bushings
crossmember bolts
shackle bushings
bell housing bolts
motor mounts
u joint u bolts or straps

Mine has always clunked when switching directions. Not sure why.

I've seen some strange "clunks" in the past, most of them are due to inadequate fluid in the trans or the TC, if you havn't done so, it's worth at least checking.

If it were not for the fact that you report smooth sailing I am inclined to think u-joints. If you're going to put some grease on the SY it's worth checking them (and greasing if it has the nipple)

Last summer I was having a lot of vibrations when driving ~40MPH, it would go away if I went faster or slower, after spending a few hours trying to debug the issue, I did the U-joints, in doing so I found that what once was nice rod bearings had been reduced to some variety of powdered metal and carbon ash, was a bit stubborn getting it out, but new joints and all good.

Also, if you're dropping the drive line, inspect the SY seal.

Pretty sure what u-joints use are referred to as needle bearings just FYI. Wouldn't want the OP to think his engine may be shot over a little drivetrain clunk!

FWIW I have the same clunk even after new motor mounts, trans mount, entirely rebuilt driveshaft, etc. I think it's just excessive backlash in my rear axle. Not too worried about it since it'll get regeared eventually.

FWIW I have the same clunk even after new motor mounts, trans mount, entirely rebuilt driveshaft, etc. I think it's just excessive backlash in my rear axle. Not too worried about it since it'll get regeared eventually.


how are your control arm bushings/leaf spring bushings/shackle bushings ? are the leaf spring/shackle/control arm bolts all tight? trans mount bolts are all tight? Front DS U joints are good?

Ultimately, it is (usually) an excess of lash, or play in the rear. I don't think I've ever had a vehicle with a tight rear end(!). One practice I've gotten into the habit of using is to let the drivetraie 'relax' when changing direction. Every vehicle is different, and will have different needs. I bought my '92 in '99, with 78k miles, and as long as I've owned it, the transfer case has beed sloppy. The pressure cable to the tranny was stuck on, meaning it shifted harshly, and liked to clunk when downshifting at a stop. Also, the previous owner must have driven around in 'Part Time' too often, leading to the sloppy TC. A stiff accelerator was the clue to the too-tight cable, and once I adjusted it, shifting smoothed right out, and no more clunk when stopping. The only remaining symptom is a very slight clunk when shifting out of Reverse, to either Neutral or Park. Nonetheless, a complete halt when changing direction is key. Reverse to Drive, or back, take your time through Neutral, and see if this doesn't get rid of most of the problem.