Gear install

Yep, there should be absolutely no need to change the carrier shims. They are two really big shims, one on each side. After you setup the dial indicator & measure the backlash, if you are within spec, then you don't need to mess with the carrier shims.

The gears don't come with carrier shims anyway, so you would need to go buy some from Ford. I didn't need to b/c my backlash was within spec.

The shim you do need to change is the pinion shim. This is done by measuring the pinion heads on both the new & old pinion with a dial or digital caliper. If the new pinion is taller, you need to remove some from the total thickness from the shims. If the new pinion is smaller, you need more thickness.

i.e. if the new pinion is .001 smaller , you need to add .001 to the new pinion to ensure proper pinion depth. The stock shim will be a big one, so you can just replace it with 2 smaller shims that equal the total thickness required.

Check out the link in my sig for more information.
Scott