Angle Gear Failure Soon After Sleeve & Seal Replacement? Driveshaf

[chriswb]

In May, my main indy mechanic fixed my failed AWD. We wouldn't know until he opened it up whether cause of failure was sleeve or angle gear, but hoping it was only the cheap sleeve rather than the expensive angle gear, I supplied him with an OEM angle gear sleeve and seal kit (http://www.tascaparts.com/oe-volvo/30787988) before he began work. To my relief, he reported the problem was not the angle gear but the sleeve and my AWD was fixed! For 5 months! Wait, what? Today I investigated a speed-related grinding noise and found that where the driveshaft enters the angle gear case the shaft has too much play (shouldn't have any, should it?) and the seal on that side has failed (angle gear case is slick with oil). My questions: Is it likely that both the expensive angle gear AND the driveshaft now need to be replaced, or just one or the other? (The driveshaft looks ok as far as I can see, but of course i can't see the end that's inside the angle gear case.) Not that it matters much in comparison, but if my angle gear has broken where it meats the driveshaft, there's no reason to think the new sleeve has failed too, is there? And, what do you think: Is it just a coincidence that my mechanic replaces the sleeve and a few months later the angle gear fails? If not a coincidence what's your theory as to the connection? Should the seal on the rear driveshaft side of the angle gear case have been replaced at the same time as the seal on the front sleeve/transmission side of the case because of the likelihood of the rear side being damaged accidentally or from drying out during sleeve replacement?