ZJ_Fisho

Hi people

New user, first post, so bear with me.
Have searched the forums and not found anything that accurately described my issue.

I have a 1997 ZJ Grand Cherokee (RHD) with 203,000Km (120K Miles) on it.
Recently I started noticing a knocking sound when slowing to a near stop, not every time, but usually after some "spirited" driving shall we say.
Seemed to be coming from the front right, but definitely the front somewhere.
It's got progressively worse over the last couple of weeks, and now it's making the same noise almost every time under brakes, regardless of use.
It's also now accompanied by a slight droning sort of noise at speed, and when slowing down, sometimes you can feel a vibration through the seat and steering wheel and there's a bit of a whine which progressively slows down to a "thump, thump thump", sort of like driving on a square tyre. When almost at a stop, it feels like driving over the cats-eyes on the curbing.
It obviously related to wheel speed, but it's not 1:1, e.g. about 1 rev of the wheel makes about 3-4 thumps.

I've captured a couple of short videos from inside the car, during which the noise is very noticible. They're on Youtube...


I've had the wheel off and checked the brakes - nothing seen. Both diffs were drained and refilled 3 months ago and the diff oil is still nice and clear.

I've got it booked in for a looksie in a few days time but would really like to try to sort it outbore they start telling me everything needs to be replaced.

Many thanks!

dave1123

It sounds like a cracked rotor, but you would have seen that. Check your front wheel u-joints. One of them could have thrown a cap.

Welcome to CF and the Jeep sickness.

ZJ_Fisho

Thanks for the reply Dave.
I appear to have CV joints at the front. The boots look good and there are no obvious tears. Still a likely culprit?

This knocking noise has appeared over just a matter of weeks, and doesn't really seem to be related to steering.

Would really like to avoid taking to the shop for diagnosis!

JBimmolate

Is it AWD? It almost sounds like a cracked or broken pinion tooth in the differential.

Miles

dave1123

If it's like my 2000 WJ, there is still a double-cardon joint in the front shaft on the t/case end. Jeep used so many different set-ups it's hard to be specific. Your 3 or 4 "thumps" per wheel rotation tells me it's before the diff. Also, it's possible for a CV joint to split it's center drive ball carrier and still look good, although it usually tears the boot.

Case in point; A friend had a 81 Chevy Citation (FWD) and noticed a rumble when decelerating. We took his front CV axle joints apart and found small dimples in the ball carriers on the decell side on all 4 joints. I asked him if he let it warm up in the morning or just put it in gear and went. He was slamming it into reverse while it was still on high idle, thus stressing the joints. This was only the 2nd year of GM's front wheel drive and problems hadn't been worked out yet. Because of the cost, he chose to just drive it. Later, he bought an 80 as a junker and we swapped the shafts. Problem gone.

It's possible one of the ***** in the CV joint is damaged also. JMHO.

ZJ_Fisho

Yikes I hope not - I gave away my spare front diff when I sold my XJ.