rear end clunk and clicking noise

[mtech325]

Hi everyone,

I've been chasing down a clunk in the rear end of my 91' 318is 24v and was looking for some pointers or suggestions.

Going over slow bumps (typically off throttle/not under load) I can hear a clunking noise from the passenger side of the rear end. It sounds like something lightly knocking.

I've replaced the subframe bushings & RTABs, sway bar links, as well as the rear shock mounts with Rogue Engineering heavy duty variants. Recently I changed out my diff mount bushing and still have the noise. I jacked up the car and the CV boots are intact, but there seems to be some extra play where the axle mounts to the output flange. I'm not sure if that's the diff itself or the axle. The driveshaft U-joint doesn't seem to be bad. I also noticed that when in gear and the rear end on stands, the LSD spins the wheels in opposite directions simply rotating by hand, so it may be worn out? With the trans in neutral, the LSD spins both wheels in the same direction as it should.

The other issue in the same area is a clicking noise when braking at slow speeds. It appeared after a 400 mile drive from SF to LA. Initially I thought the caliper was stuck or seized, but that wasn't the case after taking everything apart. I had a friend listen to confirm and he said the clicking noise is not the brake caliper.

I have a spare 2.93 LSD I can use to see if it changes anything, or should I start by replacing the axles and rear wheel bearings? Car has 147k on the chassis, and diff is a 3.23 LSD that supposedly has only 45k from a low mileage wrecked Z3-M.

Any suggestions before I have a shop look at it?

Thanks,

Joey

[mtech325]

Figured I'd update this since I have gotten most of these issues ironed out.

The brake clicking noise turned out to be the rear calipers. I replaced them with refurbished units and that took care of the noise. I think there was no more grease on the sliding bolts, paired with old rubber bits.

For the rear end clunk, I ended up installing rebuilt axles, and wheel bearings. The 3.23 LSD turned out to have bad clutches and was worn out (could spin the flanges in opposite directions by hand) , so I sourced a good condition replacement diff and most of my clunking has gone away. The driveshaft could probably do with new u-joints, but at least the rear end should be good for a while.

[mtech325]

Bumping this to confirm that a rebuilt driveshaft fixed the clunking. The rear u-joint on the old driveshaft was trashed and didn't move freely (should have known given it came from my e36 with 250k+ miles).