I finished putting in a 3.42 10 bolt posi rear I got from a friend. Its pretty much a junkyard 100K mile rear end, but the posi is good. I took all the drum brake stuff off my original 2.73 rear and put it on this one.

Some of the noises it makes are:

A washy grinding sound, kinda like draging a hammer across a concrete floor, except lower pitched. It makes that sound constantly, and slows down/speeds up with vehicle speed.

During hard turns the rear end howls. Its louder during right turns, and quieter when turning left. It only does it when going 20+mph.

I added a bottle of posi additive. I dont think it made any difference.

 

Just out of curiosity:

Did that rear end come out of a stick shift car?

The reason I ask is that I've had 3 5 speed 3rd gens. An 84 T/A, an 87 Formula, and the current 88 "Project X"; they all have given me the same problem.

The noise was that my pinion had loosened up and was slipping deeper into the rearend causing the horrible noises you describe. My Formula was so bad that when I pulled the back cover I could see pinion tooth scrape marks all around the center of the differential carrier!!

Anyway, you better pull the cover and take a look. I pulled the driveshaft out, took the nut off, changed the pinion seal which was leaking, torqued the nut back down and then tacked the nut to the pinion with a mig welder!

No problems after that! Of course, welding is not the preferred method but I wasn't planning on keeping it long. I never thought it would last forever...

... but it did!

Good luck finding your problem!

 

Wouldnt the noise during turns most likely be the posi or wheel bearings?

 

Does it look like your front pinion seal may have been leaking?

I think you better take off your cover and have a look inside. It will only cost you one rear axle cover gasket which is pretty cheap. Like a couple of bucks cheap.

You can even re-use the fluid!

Then you'll know for sure...