Carrier bearing problems.... please help!!!!

Lately my 88' XJ, which is no longer my daily driver, has been making an awful humming at any speed. I've replaced the rear axle once, the first time was due to a pinion bearing that went bad. REAL bad. The "new" Dana 35 is out of a 90'-91'. So I checked the pinion, and there is zero play. I asked a mechanic, and he took it for a spin. He thought that it was the carrier bearings. Anyway...
I got under it this morning and pulled the rear end apart. I took the bearings off, and they were REALLY pitted. I'm guessing that was the cause of all the noise. So, I took the diff. carrier down to a local engine machine shop, they took off the old ones and put on the new ones in about 20 minutes.
I went home, put it in, tried to put in the thick shims that go on the outside of the bearings. I had to tap one with a brass hammer to get it in. Problem is, my diff is really hard to turn by hand now. it seems like it is binding up. I went to NAPA thinking that I could get some replacement thinner shims, but no dice. I could drive to work and make up a bunch of different sizes, but I'm thinking that there has to be a different option.
Also, how much should the carrier be able to move along it's rotational axis?
I'm guessing that would be the "backlash"?

Seth

Backlash is the free play between the ring gear and the pinion gear, when the direction of rotation is changed from forward to reverse, or reverse to forward.

the reason it's probably hard to turn is because you have new bearings and it is much tighter. You are probably ok with it being a little hard to turn. You want a fair amount of preload on new carrier bearings. But did you have to slam them in? or just tap them in? If you just tapped them in with normal resistance it should be fine. You dont want the carrier to just slide out it should need some prying to get it out with new bearings. when the bearings break in you will loose a lot of preload. you also need to make sure your resistance isnt comming from the ring gear being jammed into the pinion. So your going to want to check your backlash with a dial indicator and make sure it's withing guidlines for that diff. probably like 6 to 12 thousanths. If there is no backlash you need to buy a install kit with shims and re shim it.

I just went through something similar witha D30. I pulled of bearings which were NTN to use them as setup bearings. AFter I got the diff setup I pressed new bearings on which were Timken. The diff got REALLY tight. After some head scratching and pulling the Timkens off and putting the setup bearings on again things got better. Turned out that the NTN's and Timkens + races are different width (measured with a digital caliper).