Sometime back I converted my stock 1971 2.56 skylark peg leg rear to an Auburn posi. Im getting that chattering noise when going backwards. I was thinking of changing the lube and was wondering how much fluid the 10" rear held and what weight it should be. I also want to get the GM posi additive. Where can this be bought and how much would I need?
Not sure where but I assume any GM dealership should have it, as well as most parts stores. They usually sell it in a single use size. You dump the whole (4-6oz) bottle in the rear and fill the gear fluid as recommended by Auburn. Don't use synthetics, or so I hear. They go against what most of the posi mfg recommends.
Thanks, Saw stuff on eBay but shipping was costly. GM dealer near me was out of the additive when I checked Friday and I didn't know if the product was available in any auto parts store.
Being that it doesn't have a GM original 'posi' unit and uses an AUBURN unit, I would use what the AUBURN tech specifies. Don't know if they call for GM posi additive, or what. Try their website yet?
Any name brand 80W/90 Gear Lube and one bottle of GM posi additive, Done. http://www.amazon.com/GM-Performance-88900330-Lubricant-Additive/dp/B0028CMPIS
Another solution is Sta-Lube brand Equa-Torque. Many a parts store carries it. It has worked great in every posi rear end I've used it in.
I used synthetic in my rear end by mistake, with a bottle of GM posi additive. I have (I think) an Eaton posi unit. No problems after many many miles.
Geez, Here is what I want to know how you bought a aftermarket Auburn posi and hooked it to a 2.56 gear...??? lol. 2.73 is as far as you can go with a aftermarket Auburn...UNLESS you are using a GM Borg Warner/ Auburn posi unitfrom 1971 1972 era 2 series unit. ?? 2 - 2.25 quarts will fill the cavity. The additive should be installed before the last quart of hypoid gear fluid as it is the imoportant part and needs to be completely used. you MIGHTY have to used 2 bottles of GM additive to quiet it down. Jim JD
Jim, I dont have my log book handy but I believe the 1971 stock non posi rear guts were replaced with an Auburn carrier and 3.08 Richmond gears which I purchased from Summit Racing. Thanks for the fluid amounts! Steve
When you guys refer to GM posi additive you do mean the "GM Limited Slip Axle Lubricant Additive" correct? Thats all they told me they sell and I bought 2 four once bottles, part # 10-4003.
Yes, it's actually part # 1052358. Look on the bottle. http://www.amazon.com/GM-Performance-88900330-Lubricant-Additive/dp/B0028CMPIS
Thanks Bottle has changed in design from the one listed on Amazon. Now it looks like a small car oil bottle. I have the part number I previously posted and my receipt shows part# 88900330 which is the old number like whats on Amazon. Parts person said bottle changed recently. Best part is I got the stuff for cost @ $7.87 per bottle! Good thing since I wanted 2. Now all I have to get is the gear oil.
Never realized how hard it would be to find non synthetic or posi / limited slip additive free gear oil. Only one I could find was Napa Premium 80/85/90. I know its not made by Napa but is doesn't say its synthetic or list any additives.
Wal-Mart by me had none today when I looked. Is their 80/90 Super Tech non synthetic and rated GL-4 only ? If so I'll check another one tomorrow.
http://www.walmart.com/ip/Super-Tech-80W-90-High-Performance-Gear-Oil-1-Gallon/16795067 Looks like GL-5. Not really sure what the difference is between 4 and 5.
Just did some research and found that NAPA gear oil part NOL 75210 is NON Synthetic and has no limited slip additives. Exactly what Auburn recommended along with the GM additive or their own additive. Local NAPA store had it in stock for $5 per 32oz bottle. Thanks for everyones help!
I just changed the rear lube and added 8 oz of the GM additive (2 bottles) to the mix. Hopefully, my snap crackle and POP will be gone! Now Im waiting for the weather to cooperate in Florida so I can mix things up and see how she feels
