Rebuilt this transmission about 2 yrs ago, the truck was brought to me because it lost reverse. At that time I found the reverse band had broken. I completely rebuilt the transmission and replaced the broken reverse band. Last moth, the vehicle owner called me and said reverse had stopped working again, they had driven the truck roughly 10,000 miles since the rebuild. They dropped the truck off at my shop last week. Transmission removed and torn down I found the reverse band worn to the metal and the planetary gear worn and scored. I found no other damage to the transmission so I replaced the planetary gear, reverse band, resealed the transmission and reassembled it. The owner of truck tells me their driveway is very steep and they back out of the driveway, up hill every morning. In an attempt to beef up reverse, I used a thinner pressure plate on the reverse clutch and added one clutch disc, which increases the clutch pack to 4 clutches. I also replaced the factory transmission pan with the Dorman pan that has a drain plug in it.
Transmission re-installed in the truck, reverse works perfectly and all forward shifting is normal.