I'm not particularly happy with my car lately. A full IRS rebuild - rebuilt diff, calipers, got the handbrake working, one of the UJs needed replacing. Big job as many of you know, and I was so looking forward to getting it back on the road.

The reason I undertook the job was that the calipers finally gave up the ghost and the diff had been leaking all over the brakes since I got the car (20 years ago) so it was time. So if the diff was bad (other than the seals) it wasn't noticeably noisy.

Now that everything is back together there is a noticeable amount of noise coming from the back end. Doesn't sound like bad bearings - not a low rumble - more just general speed related noise.

I hear no similar noise when I Jack up the rear of the car and spin the wheels or even if I run the car with the wheels I the air.

I'm starting to wonder if it's all down to the replacement mounts. Is it possible that the harder rubber on the aftermarket (and new - therefore harder) mounts is just transmitting noise that was always there through into the car?

Anyone else had a similar issue?

 

I think you're on the right track with the mounts. But check everything else for contact . The replacement uro mounts are considerably harder then the original Metalastic mounts. I recently came across a single unused metalastic original amount. The rubber is noticeably softer than the uro mounts. I think at this point URO is the only company manufacturing replacement mounts. Perhaps somebody else has a source for original mounts or replacement ones that use the softer rubber. I have not been able to come across them.

 

Can you tell if its on the outside, like from the hubs, or the inside, like its the diff whining?

 

Not able to localize it - just general noise coming from the rear. Not a whine, not a rumble. Hard to describe.

 

Wheels and tires????


Carl

 

What about the UJ covers? Maybe you aren't hearing the issue with the car lifted based on angle?

 

Same wheels and tires that were on before the work.

 

First thing I suspected, so I rested the lower arms on stands to make sure the angle was as it would be on the road. No noticeable noise there.

 

Maybe check the disc are running true, if you have had work done of the diff axle bearings/seals

Or perhaps its the new normal and you are just very focussed on the rear end because of all the work.

 

New discs and I checked the runout. I think you may be right about the new normal.

 

And you can't find the area even with it running in the air? Do you have a mechanics stethoscope?

 

Nope and yep! I know - it all sounds like I'm imagining things.

 

Seconding this - would be great to find polyurethane mounts instead of the uro ones. Shame they don't come apart so you can replace just the rubber part of the mount