When my transmission was rebuilt, the re builder replaced the sun shells with factory improved units that werte available from Chevrolet before my truck was ever even made. I never used it for towing, so it was never worked really hard that is except for my size 15 foot{no, it really is} on the throttle, but if they knew the original design was bad, weak or flawed in some way bad enough to make better ones then why the hell did they not install them to begin with???????? I will still only ever buy American cars as they are still the bestespeciall if you are a real man and over 6'6" and 320, and also add to it that if these stupid fellow Americans of mine really want to help the economy get better, then start buying more things made here inh America rather than somewhere else ESPECIALLY WHEN IT COMES TO CARS, MORONS!!!!!!