I'm replacing the gears in a 1950 1/2 ton. I bought the 3:55 gears and instalation kit . The instructions say to check the ring gear run out by running a dial on the back off the ring. The spec is +-.002. That would be a total of .004 high to low. I find I have .005 high to low. I took the ring gear off and checked the carrier run out and found it has about .0015 run out (passable tolerance). I Cleaned everything up again put it back together and run out remains the same .005 high to low. The lash runs from .007 to .014. I spoke to the guy I bought the gears from and he says he never heard of such a problem. He said it would probably be alright but if there is a problem he would warranty them. Some people are telling me I'm going too crazy trying to be too precise and these trucks weren't all that precisely built in the first place. I had to wait 2 months for these gears and I'm almost afraid the gears they replace them with won't be any better. The other problem is I probably have 6 to 9 months of work left before I will be able to drive this thing. So should I try to run them and see what happens or should I bite the bullit and send them back now?