[SethT]

Is it true synthetics w/o adding additive are ok to use with posi? MY unit is a fresh 12 bolt build with zero miles. I don't want to screw this up. Is there one fluid I should use for break in, and another for after that?

 

[70chevellemalibu]

im sure others will chime in but give a tranny/gear shop a call see what they say.

 

[davis95]

I'd go with Mobil 1 synthetic and a 4 ounce bottle of posi additive.

 

[Beaux]

Wrong forum - you're grounded.

 

[tlowe]

do not use synthetic in a eaton type posi. it is too slippery for the clutch's to work properly. tom

 

[SS70ElCaminoOwner]

do not use synthetic in a eaton type posi. it is too slippery for the clutch's to work properly. tom

I agree!:waving:

 

[Bill Rose]

After I put a new Eaton posi unit in my 68, I called Eaton and asked them what was best to use. I'm having brain fade and I can't remember what they told me, but they will tell you. They make the units, they will know whats best. Try this too..Scroll down to Eaton posi....http://www.eatonperformance.com/differentials/diffs_FAQ.html

 

[Atlast]

I just installed mine - They recommended GM gear lube with GM additive.

 

[bri2203]

I just installed mine - They recommended GM gear lube with GM additive.

Thats what I used.