The composiste STOCK balldifs for the M18T is bulletproof if you take care ofthem, neer ever stripped out a diff like that, after 6 Xray cars, and only thoose diff+ org CVDs...Glue the "D" rings on he plastic outputs. shimm it well, not to tight,not to loose..then ya go!
Not try to step on anyones toes, but the stock 18t diffs will not stand up to high rpm use. If the truck lets one tire go and thre diff heats up, the stock plastic will melt. I found installing the steel diff outdrives cured this problem, as stell does not melt easily