I finally put synthetic in my transmission and rear differential. Amazing. When its cold out and you shift a manual, it has a really hard shift because of the cold. well, with the synthetic it doesn't do that, it is great. Shifts like it is all warmed up. Plus I got an extra 2 miles per gallon.

 

If you have a Tremec Trans., you could put GM Synchromesh in and shift twice as smooth as the stuff you are using.