I recently took my truck in and had the tranny fluid and filter changed as well as the rear diff fluid drained and changed. When i got the truck back, i now notice that it shudders or slips when taking off on a slight incline, empty, or when i turn it hard to the left or right taking off. Then i don't feel it. I can put the accelerator to the floor after the truck is moving and it holds the gears and doesn't slip. I took it back to the dealer thinking it was the tranny, and they hooked it up to the laptop and couldn't find anything wrong with it. I am the original owner and it has 138,000 miles on it and it just started doing it about 500 miles ago. Is this the carrier bearing or some kind of gasket or something that has worn down. Is the angle off where the driveshaft comes from the tranny to the rear diff? Any help or advice would be appreciated.

Just a thought but the same happened to my truck after a dealer service on the diff. and they figured out they put the wrong fluid in,They went ahead an changed fluid to the right stuff an adjusted some tolerances and so far so good.