Hey guys, well I just came across a posi 12 bolt for my 72 chevelle. What I wanted to know is how many quarts of gear lube does the rear-end take and what weight and brand should I buy? Any opinions?

Originally posted by EkS:
Hey guys, well I just came across a posi 12 bolt for my 72 chevelle. What I wanted to know is how many quarts of gear lube does the rear-end take and what weight and brand should I buy? Any opinions? any good heavy duty lube will work. i use redline syn. but i had two cars to do and bought a gallon. just make sure you put the posi fluid additive in. its a little bottle of additive that helps the clutches i believe. just fill it up until oil starts coming out of the fill hole then its full. probably be safe buying 3 qts. and the additive. 140 wt. you will be good to go. i know the redline i put in is heavier than that. hope that helps. tommy

I just had a new 12 bolt posi built by Art Houser and he sent me 3 quart bottles plus the 4 ounces of posi additive that you must also add.
He also cautioned me to not use synthetic lube in a new unit as he does not recommend it with the clutches in the posi.
As stated in the other reply you add the lube until it runs out, the proper level is just below the fill hole or level with.
Use rubber gloves when installing the additive as it stinks like hell and is hard to wash out of your hands.

I just refilled the 12 bolt in my 70. It took 2 quarts and 1 tube of limited slip lube. Just use plain old 90W.

I'll tell ya tomorrow,,,I drained mine tonight,,,resiliconed the cover,refill tomorrow with synthetic lube...might be worth .02 :D

Thanks guys! I think I would have messed up my posi because I did not know about adding the posi additive. What should I look for in the additive for the posi? Sorry if I sound like a new guy, but I am.

Thank you all!

EDIT: Can anyone post a link to the actual product I should look for. That would make it easier for me. Thanks again!

Mine took exactly 3 qts of Redline.
The housing was totally dry, a completely new assembly that was installed after I had the 12 bolt powdercoated.

Most people get their additive from the local GM dealer. Its a little pricey, but worth it.

Hope this helps!

You can buy the posi additive at any NAPA store. I also recommend shopping at NAPA if you have a store close by. But any auto parts store will carry the posi additive. It will be right next to the gear lube.

one tube of posi lube and a hair over 2 quarts of synthetic lube graemlins/thumbsup.gif

Ok guys, here is another question. Do I put the whole bottle of posi lub first or last?