The long planetary pinion pins in GM 6L90 transmissions are notorious for allowing the smaller gear to burn and seize due to lack of adequate lube. This often destroys the larger gear on the other end of the pin as well. Sonnax output planetary gear kit 104584-40K contains a small gear and a large gear to replace worn or damaged OE pinion gears in the output planetary for the 6L90. The helical pinion gears are crafted from case-hardened alloy steel for added durability.