8 3/4 pinion shim question

First off, if your gears have been run any length of time with bad (read sloppy) pinion bearings, it's likely the gear set is bad too. If they get a weird wear pattern on them, they don't get better with use. But if yours is the rare exception that didn't get damaged, you're going to have to start from scratch with the pinion depth like rmchrgr said. If you need inbetween shims, I'd just mill off a little of a thick one to get the correct thickness. .005 should be easy.....400 grit sand paper on a dead flat countertop would do it in seconds. Just press evenly to keep the thickness even.