How much friction modifier?

[halfafish]

I put together a 8.75 rear end for the Dart. It has a used but good condition cone-style sure grip in it. I have 80-90 weight gear oil for it and two bottles of Ford's friction modifier. I've read some folks say use one bottle, others say use two. Any help with the correct amount for my car? If it makes any difference, it's a street car.

 

[toolmanmike]

I think everybody uses a bottle per rear end. https://www.doctordiff.com/friction-modifier.html

 

[95dakotadude]

I just used one tube on my 9.25.

 

[dartfreak75]

I used a full bottle on my 8.8 I got the motorcraft brand that was recommended for the limited slip clutches. Then used Lucas diff oil cant remember the weight it was close to whatever Ford recommended.

 

[Dana67Dart]

Cass at Dr. Diff said 1 bottle.

He recommended poring it onto the clutches at assy rather then in the oil at fill-up. Keep in mind that this was in reference to a clutch style with all new parts.

I would reach out to Cass and get it streight from him.