Recommended gear oil?

[69TAPoser]

What's the best gear oil for a Ford 9" with a Detroit Locker center? And how much do I need? (I am a new to Ford rears)

Phil

[Yoda4561]

The detroit locker isn't too picky. You can pretty much use whatever you want. A good 80-90 weight is fine for light street duty, 140 weight for towing and street/strip stuff. Dino/syn shouldn't make much difference, the synthetic will probably stay more stable under towing loads and high speed use. Capacity is 2.5 quarts, in practice a little less with aftermarket carriers and leftover oil from the last fill. You won't need any sort of friction modifier or other additives since the detroit locker doesn't use clutches.

[big gear head]

I use 75W140 with mine. I don't know if it makes any difference or not, but I use the heavier oil to try to cut down on the noise from the locker.

[JEFFTATE]

I'm gonna' try Torco RGO 85-140.

I haven't used it yet , but I've heard good things about it.