gears/speedo gear

At a bare minimum, you will need pinion shims, new pinion nut & a new crush collar. All of them come with the FRPP gears, so you won't need to buy them.

But there are some things you should buy, just in case you see that they are excessively worn and need to be replaced. The pinion bearing, carrier bearing w/ race (one on each side of carrier, so get 2), differential shaft + locking bolt. Any of those could be bad, and you want to have new ones in case they are bad.

The bearings you can get at autozone. The differential shaft locking bolt you can get at NAPA. The differential shaft is available at Ford.

When I installed my gears, I didn't need to adjust my backlash, so I re-used the 2 stock shims. But if you need to adjust backlash, you will need a set of carrier shims (available at Ford only).

The great thing with buying them seperately is you can return them if you don't use them. But if you need them, they will be there.

Replace the locking bolt for the differential shaft, no matter what. They are the weak link in the system IMO. Mine was only slightly bent, but I replaced it anyway.

My pinion seal wasn't leaking, but i replaced it anyway. I wasn't about to rip open my differential just because of a fluid leak.

But the actual differential shaft came out like butter, and installed the same. So I didn't replace it.

If you replace your carrier bearings, you will more than likely need to adjust backlash with different carrier shims. I didn't replace the bearings, so it wasn't necessary.

Use blue RTV instead of a gasket on the diff. cover. Oh, and pick up some crush collars at Napa (they call them pinion bearing spacers). If you dial in too much pre-load, you will need to start over with a new crush collar.

Check out the link at the bottom of my sig. It might give you some insight & save you some time. PM me if you need some help.
Scott