I have a 2006 silverado 2500hd 6.6l with a problem..... Driving to work, made it 50 miles and went to give it power and had nnothing. rpm's and speedometer both went up but wheels just coasted. it will grab at certain points but is not continuous. Im guessing pinion and gear ring????? is this a easy task????

 

Are you sure you didn't lose the transmission. Can you give us a little more info, miles, will it go in reverse, will it grab at dead stop, and have you opened up differential and checked it out?

 

Pretty sure tranny is still good. Fluid is red, in cross hairs of dipstick. Goes into reserve and will grab at a dead stop. I will be opening it up today to check it out