Help with 77 T/A Posi....

[bluemeanie]

Hey All,
I've got a 77 W72 4 speed car posi, (limited slip) with about 100k on it. I got the car out of storage this weekend and drove it on about an hour long trip on the freeway. When I pulled off the exit, the rear was making some strange noises. Kind of like the lugs were loose on a wheel. I checked everything out, including fluid level and carefully got it home. It never makes a sound until you drive it at a constant speed for a while, then slow down. I'm not a expert by any means but it seems like the spider gears may be binding?? I was going to pull the cover off and take a look, and if it seems fine, put it back together with a fresh bottle of posi lube and see what that does. Any suggestions on products??? Does this cover need a gasket or just silicone?? Any help or guidence would be greatly appreciated!!!

 

[melsg5]

Pull the cover and look for metal fragments in the fluid and inside the case. Check the ring bolts to see if they are loose. It uses a gasket. Any name brand, Valvoline, etc. intended for Posi rears is fine along with a bottle of the GM Posi additive.

 

[bluemeanie]

Thanks you sir,..! That's the starting point I was looking for!

 

[MNBob]

Also, check the U joints, they can make clunking noises.

I replaced my diff gasket and fluid last summer. The part number for the gasket was Felpro RDS 55028-1. I have a 1979 TATA W72 4-spd.