What kind of lube do I need to buy for a 12 bolt 67 Positive traction rear end? I did a quick search with no luck.
I do remember when I rebuilt my 69 Corvette rear end I used 80-90 and had noise, I then drained it, replaced it with (I don't remember ) and problem solved.
Mark

GM Limited Slip Additive! Add one tube of that to your regular gear lube.

Thanks for the quick response.
Would you run the 80/90 or the 80/140?

I run Royal purple full syn 75/90. It took about 2 quarts to fill up my 12 bolt.

I use the Lakewood gold colored stuff. dont need the additive with it but it is about $12 a quart.....

This is offered from the "for what it's worth" file...
I just had a 12 bolt rebuilt with ALL new parts - only reused the housing. I was told 2 things by the builder:
1. Use a standard gear oil. Do not use synthetic oil. I don't know why but suspect it has to do with the interaction of the posi additive he recommended.
2. Use the Ford posi additive. He said it works better than the GM.
As I don't want any problems, I am going to follow his recommendations.

Back in the old days, I had some GM posi fluid that was in a black can and made from whale oil. Seems like a lifetime ago...

I use straight amsoil fluid and it works just fine with no chattering.
Most synthetic lubes will not need the GM Posi additive.

-Bobby-

GM Limited Slip Additive! Add one tube of that to your regular gear lube.

Best advice IMO! There is no need to try and reinvent the wheel, when any good 80w-90 (I use Castrol) and one tube of additive will work fine. Any major brand will work fine.

GM has been doing it that way for a looooong time.



Rocky

Regular old 90 weight gear lube and a tube of limited slip additive is all you need. When it comes to lubricants, the expensive name brand stuff just isn't worth the price. The no name stuff will work just as well at a fraction of the cost.

Tom

Thanks guys,
My rear end is being set up as we speak, and tomorrow I will pick up my lubes.
I bought this car a few weeks ago, and it went right in the garage for changes. I have installed the Rally's with redlines, changed the exhaust, added gauges, and a posi with3.31 gears.
Just about ready to cruise,,,,,,,,,,,,,

When we went over our 12 bolt, the old mechanic refused to use anything but the GM oil and posi additive. He's one of the sharpest old mechanics I know so when he says something I listen. Our old 427 Chevelle went well over 150K miles with factory stuff, and the rearend is still in good shape. That's good enough for me. With all the research over the years, there is probably stuff that is just as good or better, but I'll change when I see a reason to.

Anyone have any ideas on how to get one to quit chattering. My 1987 GN chattters bad. I added a bottle of the GM stuff but it didn't help.

Paul

Add another bottle of the GM additive, also heard the Phord additive works well also.

Chattering is just the clutches trying to lock, it shows there is not enough slip to the lubricant to allow the clutches to slide.

Anyone have any ideas on how to get one to quit chattering. My 1987 GN chattters bad. I added a bottle of the GM stuff but it didn't help.

Paul My '65 started grabbing at bout 90,000 miles. Drained and refilled with Sta-lube GL-5 90 wt. No additive and no chattering since. I'd try that first, before more additive.