I've got a 07 nnbs crew cab with the 4.8 and the 4L60,and at 15k the trans started to act up on me.It would not shift out of 2nd gear.Of course it was under warranty,but I'm wondering if its something I should be concerned with.I've got 30k on the truck now,(15k on the trans rebuild).I'm just wondering if there have been alot of problems with these transmissions.I dont drive it too hard,occasional wot getting on the frwy,but pretty much gets babied.The only thing I have that COULD be a factor is 22 in wheels.Just wondering if you guys think I should think about getting rid of the truck or its just an isolated case.

 

07-08 models have been breaking sprags quite often. Which sounds like what failed in your case. More then likely it was replaced with the "heavy duty" gm version. It is a double cage unit, but the outer cage is plastic. I havn't seen one break yet, but I really haven't seen it pushed too far either.

 

Thanks Built!My plans are to put a Magnuson blower on it when the warranty is up,will I need to at least beef up the 4l60 or should I go with a 4l80?