We fully believe that, if everyone were completely truthful, virtually all failures of Sprinter lubricated parts are because of unapproved lubricants and/or exceeding the recommended lifespan of the lubricants. We always use Mobil 1 oil, change the engine, transmission, and rear end oils as recommended. If you own a Sprinter, you absolutley must do that or you will be buying new of each pretty soon. We adding a tranmission cooler as well, just to be on the safe side. Our advice is that if you can't keep a rigid lubricant replacement schedule with the reccommended lubricants, NEVER own a Sprinter!