I finally got moving on putting an LSD into the rear diff of my E53. After some research and reading I opted for a Quaife LSD, which uses sets of helical gears in the carrier to seamlessly transfer torque to the side with more traction. Plusses are that its seamless in its operation, quiet on the highway, progressive and most of all, they make one to fit the E53 rear end....supposedly. I half expect something to show up that the ring gear won't fit on.
Since the X is my daily I bought an complete diff off of ebay to rebuild and am pretty happy that what showed up is in very good shape. It had obviously been rebuilt at least once, and fairly recently, and the oil was very clean with no debris in it. My initial plan is to not touch the pinion gear since it feels smooth when turned and the pinion gear looks like new. Those bearings are a pain to remove without a press, but should last for a long time if the diff is set up correctly. In fact, the output bearings too should last the life of the X5 generally, but new ones are needed for the new diff as they can't be removed and reused.
The stub axles pop out with a crowbar and the splines look factory fresh and the oil seals pop out too with long bar and some persuasion. Things came to a screeching halt then as I broke two snap ring pliers on the bearing retaining snap rings, which double as spacers. Northern tool came to the rescue with a larger (internal ring) tool and I wrestled them out today.
The output bearing races then simply fall out with the snap rings out, unlike the pinion races which need to be pressed or hammered out with a punch. With the races out the diff carrier can be eased out of the pumpkin, and disassembly is complete. These are 188K BMW "medium" diffs (no output flanges), so its a pretty simple job with the right size snap ring tool. I labeled the kept the races as I'll toss toss the diff carrier with its bearings in the parts pile, just in case...
As far as new parts, I have output bearings and races coming, and the Quaife will have new seals and clips for the stub axles (I think) with it when delivered this week. Quaife, and the shop I bought it from, claim that the same shims can be used without screwing up backlash, etc. so it is key not to mix the snap rings up before labeling them "L" and "R" with a sharpie. Assembly should be quick, in theory. I intend on testing backlash and how the gears are meshing with colored paste once I get it back together with the LSD.
Shim sets are available for these 90MM non flanged output cases, but hopefully I won't need to spring for it. Sadly, the output bearings are difficult and expensive to find. New ones are needed for the new diff carrier. The pinion bearings are much more common and less expensive.
Next up: get the impact out and hopefully the ring gear will play nicely when I try to remove it. I'll also do a deep clean of the pumpkin and cover while I wait for the quaife and bearings to arrive.
One other note, with the old rear diff out I was able to compare it to some pics of the front diff carrier I found on line. They are different in width it looks like, and the front ring gear is held on by 8 bolts while the rear has 10.
Presumably then the same quaife unit cant be used up front.