Positraction additive

[Patrick B.]

[Joe L.]

Re: Positraction additive

Are there aftermarket posi additives available at auto stores that are equivalent to the GM brand additives?

My general Chevy shop manual says the cold refill level in the car is 1/2” below the fill plug hole. Does this sound right for Corvettes as well?

Patrick------


There are many posi additives on the market as branded under Red Line, U.S. Standard Gear, Yukon and others. AC/Delco also offers an additive which is the same as that available through GM dealers. If it were me, I would look for one that specifically says it meets GM standard 1052358 or 88900330.

GM specifies that the rear axle should be filled to the level of the plug with warm fluid. There is no cold fluid specification but 1/2" below the filler probably would not be far off the mark.

[Duke W.]

Re: Positraction additive

Clutch type LSDs around the world all use the same basic technology and need the same additive. The NAPA part number is NCB 4285V. You should be able to cross that or the GM numbers at any parts house, so buy on price and convenience.

Duke

[Mark E.]

Re: Positraction additive

Patrick------


There are many posi additives on the market as branded under Red Line, U.S. Standard Gear, Yukon and others. AC/Delco also offers an additive which is the same as that available through GM dealers. If it were me, I would look for one that specifically says it meets GM standard 1052358 or 88900330.

GM specifies that the rear axle should be filled to the level of the plug with warm fluid. There is no cold fluid specification but 1/2" below the filler probably would not be far off the mark.

Good advice... look for the GM spec. Posi additive is one of those things I don't shop to save a buck. I just get the GM additive and I don't have problems.

[Dick W.]

Re: Positraction additive

I was taught to insert your little finger and bend it at the first joint, if it touched fluid, it had enough

[Gary R.]

Re: Positraction additive

If you have posi chatter you should use 2 bottles of the additive. I buy it by the case from Summit

[Joe L.]

Re: Positraction additive

If you have posi chatter you should use 2 bottles of the additive. I buy it by the case from Summit

Gary------


I use two 4 oz bottles even if I don't have posi chatter.

[Patrick B.]

Re: Positraction additive

Thanks fellows. I wasn't as concerned with saving a buck as much as getting some additive right away if the Chevy dealer doesn't have it (and I can't remember when they had anything that I wanted). I will see if the NAPA 4285V cites the GM specs if the dealer doesn't have it.

[Joe L.]

Re: Positraction additive

Thanks fellows. I wasn't as concerned with saving a buck as much as getting some additive right away if the Chevy dealer doesn't have it (and I can't remember when they had anything that I wanted). I will see if the NAPA 4285V cites the GM specs if the dealer doesn't have it.

Patrick------

This additive is so commonly used for GM cars and trucks that the vast majority of dealers ought to have it. GM #88900330. Call them up and ask if they have that part number in stock.

[John F.]

Re: Positraction additive

Can you use Castrol Axle Limited Slip SAE 80W-90 API GL-5?

[Patrick B.]

Re: Positraction additive

The Chevy dealer had the GM additive for $13.50 a 4 oz bottle.

[Chuck M.]

Re: Positraction additive

I just ordered the GM additive from Amazon for $11 and some change per bottle.

[Duke W.]

Re: Positraction additive

Any oil with the API donut and SAE 80W-90 GL-5 is okay to use. Just because the label says something like "suitable for limited slip axles" or similar verbiage DOES NOT mean that the product actually contains the additive. Read the label and if it doesn't specifically state that the product actually CONTAINS the additive, assume that it does not.

Duke

[John F.]

Re: Positraction additive

Thank you Duke!

This is what Castrol website says. "Formulated with lubricity additives to reduce friction and operating temperature in limited slip applications. I would take, that it does contain the additive.

[Duke W.]

Re: Positraction additive

Maybe... it seems a little vague. I would prefer something like "formulated with a friction modifier additive to prevent clutch chatter in LSD axles"...give it a try and if the axle chatters you will have to add the additive. Let us know how it works out.

Duke