Posi unit recommendation for 12bolt

[bry593]

Brian also votes for Eaton True-trac helical locker.

This has no clutches to wear out and does not require limited slip additive. Just use regular old 75w90 gear oil.

Another cool thing is that unlike a traditional locker, you don't have to worry about getting off the throttle before entering a corner. The true-trac acts like an open differential until there is a rotational difference between the wheels.

A bad thing about this design is that it will not lockup if one wheel is completely without traction. For example, if one wheel is in a low mud hole, it will just spin. The fix is to lightly apply some drag to the spinning wheel (use the brake pedal) and it will lock right up.

Anyway, this is the best you can get for a daily driver. If you are off-road or really trucking, get a Detroit Locker. These are bullet proof and deliver 100% torque to both axles. They do require some thought about how you drive or you can have a really bad day. If you approach a corner nearing the limits of your handling, as soon as you left off the gas in the apex, the locker unlocks and this throws the dynamics of the chassis off. Can cause you to lose control.