'69 differential
Thread Starter
Drifting
Joined: Feb 2001
Posts: 1,542
Likes: 64
From: new ulm mn
'69 differential
Just bought a '69 427/400 with a 3.08 rear end. The previous owner rebuilt the differential and said he set it up "too tight" causing it to clunk and jerk in corners. He said that he added the posi additive. My question is is this something that will " wear in" in time or is it something that must be redone. Also, am I doing damage by driving it now. :confused:
Drifting
Joined: Mar 2001
Posts: 1,514
Likes: 1
Re: '69 differential (loflite)
My differential was popping after a highway run. I added the posi additive, didn't help. Sucked out all the old fluid added 2 bottles (8 oz) posi lube and 1.5 qt new 80w-90 oil, that got it fixed. Hope that helps.
Scott
Scott
Pro
Joined: May 1999
Posts: 749
Likes: 2
From: Gabriola BC
Re: '69 differential (loflite)
I have had a posi that clunked so bad you were sure it was destroyed internally. I changed the fluid with 2 bottles of gm posi additive and it was as smooth as could be. If the posi was set up with heavy springs they are not as smooth in a turn. That was usually done for drag racing and with 3:08's yours probably was not set up that way.
bob
bob
Racer
Joined: Jul 2000
Posts: 289
Likes: 0
From: Norfolk, CT
Re: '69 differential (loflite)
My rear also clunked during cornering. This is not uncommon. Don't be afraid to add a second bottle of the posi fluid. Mine took two to get it to quiet down. That's a lot easier than pulling the rear.
