Powr-Lok swap questions in 741 case.

yep, it is a good idea to replace the pinion bearings while out if you don't know when they were last changed. (Although I have run used ones before as well.) The pinion takes more load and spins faster than the carrier bearings. If running 3.55 gears, the pinion spins 3.55 times for each one revolution of the carrier bearings so, faster and more revs puts more wear and tear on it (more heat as well).