What i beleve comes stock in the revo is diff grease witch in bashing works great but if you want somethang better then try 30000 in the front and 10000 in the rear work great for track running and better steering response. If you want to lock your rear end to an possi then try 100000 wt it will act like and possi. to keep in mind that when you are on paved roads with an possi rear end on turning you can shear drive train componets because one wheel wants to go slower than the other but in dirt its an blast. So it depends on what type of driving you do. Try starting from there and working up or down to your what you want. an lot of trial and error, and have fun.