Originally Posted by polyspheric
Advantage to underdrive: the driveshaft speed remains at the pinion gear speed - low. This is always a negative factor with high cruising speed and deep overdrives: the D/S "thinks" you still have a 4.10:1 axle, and reaches its critical (safe) RPM at a lower MPH.

That be true work
That is one of the good things about a two speed rear end, I wish someone would make them for us hot rodders now luck

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)