Got a 02 gmc Sierra 1500 with the 4.8. The truck had 3.42 with no limited slip. I just put a g80 gt4 (limited slip, 373) in it. Both rear ends are disc brake. I have the vin for the truck it came out of and it shows it was a 4.8 ext 2002 chevy 4x4. I got new rotors and pads for it and went to put them on and the caliper bracket fits perfect but the caliper itself won't go on. I compressed the piston all the way in and everything but it will not go back on at all. I got the 325mm rotors and I called the parts store and gave them the info of the truck the rear end came out of and the part a numbers are the same as my truck for the caliper, bracket, and pads and rotors. I have no clue why they won't go on. My caliper is single piston. Any ideas?