Rear end whine

[Bearcuda]

Hey all, I just got a 71 340 4 speed Cuda. As I go through the gears I'm hearing a whine or something from the rear area that seems like it's coming from the differential. It's pitch follows the speed of the car. It's got a newer rear, and I've never worked on these 8 3/4 rears before. Could it just need an adjustment of some sort? Something too tight? Anyone experience this before?

[MoparLeo]

Jack it up and put some good jack stands under the axle housing on both sides of the differential. Block the front tires. Have someone get in and start the car, slowly put it in gear and listen to the rear area see if it is coming from an outer axle bearing or from the differential area. Be careful of the spinning tire.

[chaps70rt]

I wonder if they forgot to add the Mopar Rear-end additive??

Sounds like a bad bearing ....... had similar problem and had to rebuild.

[Racer57]

When I bought my Cuda the rear was doing that. 1/2 of bearings and gears were pitted from rust. It was assumed that it had sat on floor for a long time and the top half had rusted. 

[Chryco Psycho]

WHine is never good & rarely does adjustment help , something is wrong & & that usually involves parts .

[Bearcuda]

I think the crush sleeve for the pinion wasn't done correctly.

[Dmod1974]

If that's the case you'll notice lower than normal turning torque or even play in the pinion shaft.

Pinion bearings tend to whine and carrier/axle bearings tend to do more growling due to the speed at which they turn.  Gear mesh issues tend to cause clunking (excessive backlash) or howling.