We pull Steve's transmission at the end of the season, and this going on the third season with him we are putting the same clutches back in. This thing is a monster. Since we went to the Aermet input shaft, (knock on wood) we have not broke a hard part in the transmission.
Torque converters were our bane, with the fat shaft and a 3 disc converter we couldn't even get a pass out of it. Now with the aermet and the DPC 4 disc, we will get a couple events out of a converter. Playing with nitrous vs lock up at the end of the season seemed to stretch that out some too.
So Commercial Powertrain Transmission = Once a season pull it and go through it, for our peace of mind.
DPC 4 disc converter = Probably 3 a season. We have tried several other brands some of which made one dyno run and broke on the second, so far we haven't found a converter that will take more abuse, or a guy better to work with then Phil.