Hissing/dragging mystery noise from rear end, stumped!

[mr.vang]

Unscrew the axle from the diff, start the car and put it in gear while its on jack stand. If its still noisy, its the diff. If not its the wheel bearing.

[Wanganstyle]

If the whine is related to LOAD and throttle position and will still make a rumbling in neutral while coasting in neutral...............


usually the diff pinion RACES x2 will have worn and the 2x related bearings are dying.
the entire load of the car is put on these 2 bearings/races.

a slight amount of metal in drained differential oil will show this;

[cabriodster87]

My diff sounds like a swimming pool pump.

[goldenbb]

Please keep this thread going! I'm concerned about a similar sound--it speeds up and slows down with the car. Rear rotors and brakes are brand new. Haven't looked at the e-brake, but I don't think it is too badly out of adjustment. I replaced a front wheel bearing, so I am suspicious of all the bearings at this point.

The guy I bought it from was not entirely truthful about its condition, so if something major were wrong like the rear diff, that kind of fits why he was selling it.

[sweet3]

Same issue here. Changed rear wheel bearings, diff oil, rear brake pads and rotors, e-brake shoes, center support bearing and still have a noise :/

[Bigboy740il]

I feel your pain OP. I have the same noise and have changed the diff fluid, wheel bearings rebuilt calipers, changed brake lines, and still have the same noise. My next step is guibo and center bearing, and if that doesn't work i will change the differential for another.

[jlevie]

A dragging/scraping/hissing noise from the rear wheels that doesn't go away with application of the brakes or parking brake won't be from dragging brake shoes or pads. It could be from something in the parking brake mechanism, which should be obvious once you pull the rotors. If not from the brakes or backing plates, the next most likely cause is a bad wheel bearing. A bad bearing in the differential is a possibility, but I'd change the wheel bearings before messing with the differential.

[jeffnhiscars]

4.10 open here as well.

Before I started replacing anything other than the diff oil, I'd take a close look at the e brake. If its adjusted that poorly who's to say it was installed right. It's not uncommon for the shoe retaining pins to corrode or pop out which could easily cause a noise such as you describe.

[Eddie Haskell]

Could be brake pad drag. If the sliders are sticking or if the caliper piston seal is sticking to the piston (stuck corroded bore) the pads will drag on the disc. Happens frt and rear. The rears are easy fix. If Girlings on frt. Pita. There is a technique for the piston gaiter on Girlings. If u dont follow you will be chimping, Grasshopper. Seems as though disc runout would alleviate the problem but sometimes it dosnt.

[MoreMayhem]

as far as I know the automatic cabrios came with 4.10 open diffs, there might be other difes on different year models,
mine is a 1991 plastic bumper automatic
Henry

That makes sense. I'm 5 speed.

-MM

[MTechnikII]

as far as I know the automatic cabrios came with 4.10 open diffs, there might be other difes on different year models,
mine is a 1991 plastic bumper automatic
Henry

[MoreMayhem]

Non LSD diff on cabrios

Does this mean that the LSD diff on my cabrio isn't original? I received zero history on the car (auction) and it is a 3.73 LSD.

BTW: mine makes this noise too.

[long tall eta]

you can get a used open diff for a couple fish heads and a bowl of rice.

[Deutschbag]

Haha okay cool. That was my woman's solution to the problem, day 2 she got a new stereo installed :D But good to know it's not a huge problem, just kind of annoying because of my OCD with cars. Thanks man :)

[MTechnikII]

I've owned the car since April 2003 and it has hissed ever since I got the car, in the beginning I thought something is rubbing against a shaft or drive shaft, oh easy fix I'll fix it soon, but when I didn't find anything rubbing or touching I was told its inside the diff, so I just turn the radio up and the hissing goes away :)
Non LSD diff on cabrios
Henry
the car has over 220kmiles,
it's not the Mtech I own , the Mtech is quiet no hissing , it has about 130kmiles