I'm running the 48 pitch gears with a 8.5 540. Maybe it's because it's not a high torque motor or just because I'm use to setting gear mesh on 64 pitch on-road gears (and thus am VERY anal about it) but I've had no issues with stripping gears. Truck is really quiet compared to some of the others out there too.

And for those of you changing diffs between heats in 5-10 minutes, you MUST be using the electric drivers to do it...even then 5-10 minutes seems REALLY fast. Took me well over an hour to change out the fluid in my front diff and that was putting it back together with an electric driver...had to take it apart with hand drivers.