I have been pushing over 900 hp thru one of the first Revmax 1000 series for 15 months now in my 12 mega cab. Mine does not shift hard at all its firm and the converter gives a solid bump in lockup but never considered hard. During normal driving I don't have lockup until mid 4th gear so its hard to bang a shift or shock the trans or drive line. I haven't had any issues at all with my 1000 series it has been a reliable solid performer for my driving style. I have only ran two MCC tunes the entire life of the trans set to kill mode all the time.
I built my truck brand new off the dealer lot with less then 40 miles on the truck. At the same time I bought one of the first public 850 models from Revmax in late 2012. I held great for 14 months of use. I proceeded to shorten all 6 of my rods .110" with only 13,000 miles on the truck. That was in 2013 when tuning was not great and the power was made too quick with compounds. Best estimate at the time was about 700 hp because tuning limiters were holding it back. Its was still good enough to lower the compression and spit raw fuel out :hehe:
I pulled the motor and built it with the mods listed in sig. This trans has not had an easy task at all and I have put it thru the pace's now for 15 months. With great tuning available now this truck is a beast. I have had great experience with Revmax and their products.
Something was not right if you were experiencing those hard banging shifts and like Kronk said breaking the billet input shaft is very rare pointing to some kind of issue. Do yourself a favor and ditch the 2 pc drive shaft best thing I ever did as I caught mine early on with my first setup. I replaced it with a 5" heavy wall aluminum one pc and its night and day with added traction aids and now is stable and straight when hammered down.
Chris