Clunking on deceleration

Hello All,

I have a 1996 Cherokee (XJ) 4.0L Manual transmission NP231, Chrysler 8.25 rear.

I put a budget boost on it about 75,000 miles ago, and also have an xfer case drop.

Recently it has started giving me a clunking when I let off the gas pedal. It actually seems to be worst when coasting in neutral or with the clutch in, but I get some clunking with engine braking.. Nothing with acceleration or steady state load. I don't really feel anything, just hear a metallic clunking that seems to come from the rear end.

This is not something that has gotten progressively worse... It was fine one day and clunking the next.

After some searches here I checked my u-joints and differential inputs thinking it could be a pinion bearing or u-joints. Neither driveshaft has vertical or horizontal play (Front I can wiggle a tiny bit, maybe 1/2 mm or so). All U-joints also seem fine. Fluid levels are full.

It has been suggested that I check the passenger side engine mount for broken bolts (on my list) and put grease on the x-fer case output shaft. Are these valid points for this type of problem?

What's the next place to look?

Thanks!

checka nd replace if needed : motor mounts, tranny mount, U joints in rear DS, tcase mounting bolts, outer axle bearings, brake calipers, tranny mounting bolts, grease everything if you have greased it all recently . Check leaf spring bolts, shackle bolts, control arm bolts never hurts to pop the rear diff cover and take a look inside either if you havent done so recently.

blondejoncherokee said:

checka nd replace if needed : motor mounts, tranny mount, U joints in rear DS, tcase mounting bolts, outer axle bearings, brake calipers, tranny mounting bolts, grease everything if you have greased it all recently . Check leaf spring bolts, shackle bolts, control arm bolts never hurts to pop the rear diff cover and take a look inside either if you havent done so recently.

Click to expand...

Thanks,

Just replaced fluid in both diffs and transmission. Did not see anything amiss in either diff.

Did not find any play in front or rear u-joints

Did not find any play at front or rear axle inputs.

Have checked suspension mounting points, and there is some rust, but everything still seems solid right now.

Still to check
Motor/Trans mounts

Grease

I don't think it has anything to do with brakes as the clunking is independant of any braking action.

Someone on another forum suggested "slathering grease" all over the transmission output shaft splines and surrounding area. Does that make sense?

Thanks!

see how much free rotation there is in the yoke going into the rear axle. I can turn mine almost 1/4 turn before the pinion engages the ring gear (which is WAY too much).

There is neglibible rotation at the input for either axle. A bit more in the front, but at the rear maybe 2-3 degrees of free rotation max. Front is maybe 5 degrees.

Have you greased up your slip joint?? I mean, remove the joint at the rear yoke, remove the shaft and grease up the slip joint. As much grease as the gears will hold. I've done this on a couple Jeeps with the "clunk" and it's like friggin magic.

P.S. I know it's not really magic...but it worked for me.

I had that suggested over at JU and have not tried it yet, I was curious what the logic was with it, I guess just to fill up space?

You are talking about the output shaft of the x-fer case correct? Remove the driveshaft, and that joint will pull out of the xfer case?

The logic is to allow the yoke to slip on the shaft.

Remove shaft, pull yoke out of transfer case, lube splines, reinstall

That makes sense!

Hello everybody! this is my first post. I´m with the same problem, but I greese it and the clunk continue.
I make this video to show you my problem.

https://www.youtube.com/watch?v=qTgMopMD39s

Sorry my bad english.