Thanks all! I have a 1991 YJ 2.5/AX5. I'm getting ready to do the internal to external slave swap and have the first of a bunch of questions (more as I progress) I'm sure. I got donor parts from a 95 YJ (bellhousing, fork, retainer shaft, etc.) I cleaned up the bearing retainer as it had the donor throwout bearing on it. Everything was a little crusty so I degreased everything and used a gray scotchbrite pad on the shaft and then followed with oiled 2000 grit paper to clean the shaft up. Now, when I fit the old throwout bearing back over the shaft, there's a tiny, tiny bit of play between the bering bore and the shaft. Is there a spec on acceptable play between the two? I'm thinking there should be a little to accommodate grease? Second question: I'm going to replace the U joints in my driveshafts and am looking at the Dana/Spicer 51310X. They're the non greaseable/heavy duty units. Does anyone have any input on these particular units?