I’ve finally embarked on a slow motion LSD upgrade to my rear diff. I’ve inadvertently gotten into some icy and muddy farm roads while bird hunting with the X5 that the DSC simulated LSD really struggled with. I’m very careful, especially when I’m in remote areas, but occasionally I have blundered onto a farm road that looked ok, but had me really worried that I was going to have to walk out.
I decided to go with a quaife helical design for a few reasons. They make one that actually fits the E53 3.6 rear diff (a big plus), by all accounts it’s bullet proof, it has excellent highway and around town manners (unlike a true mechanical locker), is relatively quiet, and is plug and play…no adjusting, special lube, etc. The drawbacks are that it isn’t the best off road LSD design and will still loose traction if both wheels have little or no traction. However, this can be overcome, apparently, by tapping the brakes to simulate traction. Therefore they tend to work well with DSC systems as well.
Since my X5 is a daily driver, I bought an EBay complete rear diff into which I will install the LSD, along with a full rebuild. I’ll swap it in when I’m done, or have my Indy do that bit. That way I can always swap the original diff back in if I don’t like it. To that end, I’ve been struggling to find part numbers for the bearings and some other bits and pieces. BMW wants to sell complete rebuilt diffs, not internal parts it would seem. However, the Quaife BMW distributor (Birds Automotive) in England was kind enough to drop the full parts list on me. Cut and paste below….I expect much of the below would work on the front diff too:
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1x pinion seal (BMW part number 31507609535)
1x pinion crush tube (BMW 33121744368)
1x pinion securing plate (BMW 23211490120)
1x pinion bearing front (BMW 33121204312 or Timken HM88542/HM88510)
1x pinion bearing rear (Timken HM801349/HM801310)
2x output bearings (FAG F-801298). Or you can use a ball bearing style used on later models which is the same size (FAG F-234976)
And the last thing is 2x output seals but we supply those FOC with the Quaife.
We would normally order the pinion seal/tube/plate from BMW then order the bearings from someone like
https://www.bearings-online.co.uk/
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I’ll post a write up when I get to this project. Hopeful before early January when I’ll be headed north again with my pups to chase birds.