Good stuff.,. I just bought some synthetic gear oil for my 4 speed, $28 bucks.,. yikes

what kinda 4 speed? brass synchros? I have heard that synth stuff doesnt exactly work well with brass synchro'ed old school 4 gears...your better off with cheap dino oil...apparently the synth is too thin and doesnt provide enough cushion or lubrication, and grinding seems to be a common problem
I disagree

.,. The synthtic oil elements are ALL of uniform size and I have always added Molybdenum (Moly Slip, Cam Lube) It has the ability to withstand extreme temperatures and has a high resistance to corrosion, it also has one of the lowest coefficients of thermal expansion among commercially used metals.,. this moly grease also thickens the oil.
I just reassembled a Borg Warner Super T-10 that was behind a stout Big Block for several years.,. It was like new, when I ripped it apart and only needed seals and a few new thrust washers and gaskets.
I use Moly in my rear ends too.

:)