Yes, I know of a place that sells those pieces seperate. I get a lot of my misc. 5-Speed parts from there.
The place is called Blumenthal Manufacturing. The are located in Oklahoma City, Oklahoma, U.S.A.
I do not have a contact number though. Do a search on the web for them, i believe they go by Blumenthal Companies or something on the net. Very good customer service, and they can get practically every individual piece that you will need.
You might acheive the best results by calling them. Larry Church used to be the man to talk to, but i was told last time he called he was moved up to a new position. The man now is a guy named Jeremey. Ask for him, if the operator asks, I belive he is in the light-duty manual tranny section. Call them, you won't be dissappointed.
I am going through this right now also. You don't wnat to change just 2 of the gears in the rear. Change all 4 you can buy a kit from your ford dealer(pn: 2L1Z 4215EA) It comes with the 4 gears washers and the carrier pin bolt. The part number for the pin is E9AZ-4211-A. I just happened to have them sitting next to me.
Ford wants $130 for that kit! I've already spent almost $370 on the gears, all seals, and ALL bearings in the rear.. and i still need new clutches.
$370+$130+$80 = $580 (canadian) to rebuild the rear end!!! Thats a lot of cash! I guess im doing it the right way the first time, this rear better last a while.
Why didn't you get an Auburn or an Eaton differential instead of rebuilding it. It worked out cheaper for me to rebuild mine it sounds like replacement would have been better for you.