Avoid failures and comebacks by cleaning the lube passages and installing the new Sonnax output planetary lube dam (p/n 104584LP). The output planetary assembly in GM 6L80/90 transmissions has a lube dam, or cover, that directs lube oil flow to the planetary lube feed passages. Over time, sludge buildup can occur, which chokes off lubrication and leads to comebacks due to failed planetary assemblies.
