I own a 2002 Mini Cooper (R50), a Model Year infamous for its failure-prone 5-speed manual gearbox. When failure occurred I replaced the whole starter motor - flywheel - clutch - gearbox - axles assembly with one from a 2005 Cooper S.

To my delight, the gearbox version I got is a "BKL", meaning "factory fitted with limited slip differential". The difference it makes is so marked and pleasant (way faster around corners, grippier, more solid driveline feeling) that I got interested in the tech of LSDs / self locking differentials.

To my big surprise, I found NO source telling what type of LSD the one fitted on some 2005-2006 R53 MINIs is. I think it falls in the clutch-type category, but was unable to find any other kind of information, let alone a datasheet of some sort.

May you help me in learning more about the specific piece of hardware I have? It is a surprise to me that such a significant dynamic improvement fell "under the radar" of the enthusiasts...

  • I've looked around, probably seeing the same things you did. I've not found how the stock LSD works, but found several aftermarket units. That doesn't do you much good, though. From what I've read on the forums, there's not very many happy owners of the stock LSD (new or old versions), mainly because they say the units like to jump around a lot (one side locks, then power transfers over to the other side, which causes all kinds of gyrations). Hoping someone with some MINI knowledge will pipe in. Commented Dec 1, 2017 at 21:26
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    As far as I can tell the Getrag 285/gs6-85bg TBKL PN 23007574848 has a 25% lockup and uses a Posi differential. @soolus seems to have it.
    – Ben
    Commented Dec 2, 2017 at 3:15
  • @Ben thanks, googoling "Posi" results are differentials made by Eaton. Is posi just a type of diff and Eaton is good at google marketing or Posi specifically refers to Eaton's product line? Commented Dec 2, 2017 at 13:26

1 Answer 1


The R53 is a Getrag GS6 and has a 25% locking limited slip. If I'm not mistaken, it is a clutch-type.

As far as a lack of information, you'll quickly find that most MINI owners just don't care what's in the car, just how expensive it is. ;)

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