I Hope So!!!
Back in the early spring I went ahead and changed the differential fluid in my '79. No issues at the time / just maintenance.
As I remember I couldn't pump out more than about a quart and a half using a hand pump.
I added the required 2 small bottles of GM Posi. Additive and a quart of GM Rear End Axle Lube. It wouldn't take in any more fluid than that.
About two weeks ago I started to hear and feel a very small binding in the left rear wheel when making left turns only. It was not very loud and only happened during roughly 1 in 10 left turns.
Today I added one small bottle of GM Posi. Additive and closed it up.
Then I drove in figure eights for about 15 minutes and was able to pump out only about a quart and a half of fluid from the diff.
I went ahead and added two small bottles of the GM Posi. Additive and a quart of GM Rear End Axle Lube. It would'nt take in any more fluid than that.
So far no more noises or binding feelings from the rear end during left turns or anything else.
Although I have not been able to remove all or most of the fluid in the diff. , is the new appx. quart and a half of Additive and Lube enough to really improve the diff?
Am I missing anything?
I'm hoping to avoid a costly repair.