What typically makes a rear-end humm or whine? I have GM 3:42' s installed, over the years they have become noisy, noise increases on the highway as well, louder over 100 mph. Sound also changes pitch when you are accelerating and then coasting or removing your foot from the gas ( louder when coasting ). Does not clunk and posi works fine, fluid with GM posi additive recently changed.

Is it the gears, bearings, carrier ???


Thanks

 

I had a similar problem a few years back with my car. Turned out to be the carrier bearings. Since I don't have the expertise in the rear diff arena, I took it to a local shop. It wound up costing me about $500 to have him fix it.
No troubles since then.

Good luck,

Jeff

 

Typically gears are noisy because of back lash being too tight, or wrong pinion depth causing the pattern to be off. If they have been in for years and quiet.. and now they are suddenly getting noisy, its most likely a bearing going bad. The other ways to get the noise would require phisical movement of the shims ect. Each axle has a bearing, the carrier has 2, one on either side. And the pinion has 2, one front and one back. Most likely not an axle bearing. You would be able to hear a distinct differance from one side of the car. Sounds like a good time to throw a set of gears in it along with new bearings and seals.

 

Interesting, thanks guys.