Diff oil question
Thread Starter
Instructor
Joined: Apr 2006
Posts: 206
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From: Ofallon MO
Diff oil question
I bought the 2 bottles of GM gear oil and 1 diff fluid and added to diff. I then realized I probably should of bought 3 bottles cause I wasnt up to the fill level. I then went and bought some castrol gear oil that was EXACT same weight as the GM oil to top off. I was told you can mix brands but not weights. Is this OK? My clunk hasn't gone away so I was thinking of adding another bottle of additive. But now I'm wondering if I should drain it all again and start over?
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
I think it depends on how bad it is. I did a '75 several years ago and the noise persisted, despite figure 8's. I was advised to change it again and after doing so, all was fine. Later, I did my '67 and by the time I backed out of the driveway, the noise was gone. Some do add 2 bottles, but I never have. GM says 1 and that's good enough for me. Glad yours is OK. 
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Sorry, I misread your post. Have you tried the figure 8's yet? If that doesn't do it, I'd change it again. You can add a drain plug to make this job easier and to get virtually all the old oil out. Have a look:
http://forums.corvetteforum.com/show...r+fluid+change
http://forums.corvetteforum.com/show...r+fluid+change
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