Differential Lube for a '64 w/ Pos. Trac

[Garry E.]

Can someone remind me of the type of oil I should use in the rear end of my '64 w/ Pos. Trac.....? I've removed the rear cover and drained the old oil and am ready to re-fill it......

Also, does anyone know the GM/Chevy part number for the special Pos. Trac. lube that is added to oil in the rear end? I've been told to use either one or two of the small bottles of this special lube. Which is correct?

thanks

Garry Eastwood
#38705

[Joe L.]

Re: Differential Lube for a '64 w/ Pos. Trac

Can someone remind me of the type of oil I should use in the rear end of my '64 w/ Pos. Trac.....? I've removed the rear cover and drained the old oil and am ready to re-fill it......

Also, does anyone know the GM/Chevy part number for the special Pos. Trac. lube that is added to oil in the rear end? I've been told to use either one or two of the small bottles of this special lube. Which is correct?

thanks

Garry Eastwood
#38705

Garry-----


I use GM #1052271 SAE 80W-90 lubricant in the rear end. However, this part has been discontinued and replaced. I don't have the new part number but your GM dealer should be able to provide the supercession for this number.

For the posi additive, the part number is GM #1052358. Personally, I use TWO bottles. When I've used one bottle, I've had problems. When I used two bottles, I've never had problems.

[John F.]

Re: Differential Lube for a '64 w/ Pos. Trac

Just go to O'Rielly's. They have both. I used two of the posi bottles.

John

[Jephrey S.]

Re: Differential Lube for a '64 w/ Pos. Trac

Heed the advice about using 2 bottles of additive. I foamed my rear twice in as many weeks using only 1 bottle. I put in 2 bottles of additive like the experts here said and my differential problems went (and stayed) away.

Also, when the "expert" at the parts store tells you that the fancy new 80W-90 gear lube you are buying doesn't need the additive anymore, just smile, nod your head, and go buy your 2 bottles of additive and put it in anyway. Your posi clutches need the additive.

[Gary R.]

Re: Differential Lube for a '64 w/ Pos. Trac

I use Lucas 85-140 gear oil or 90 wt gear oil with 1 bottel of GM additive. If you find the posi hammers after 1 bottle of additive you can add the 2nd, if it still hammers then only going into the posi will solve it.