Yeah a 3.64 diff swap is on my list for sure, and easier that I anticipated to swap. I have the 6-speed, but first gear is still just as tall.
Hell, I should hook up the plow and let the X5 become a farm tractor for Pete's sake!

There have been some cheap ones on ebay that I've seen. Lot of times you can make a deal for both diffs from whomever is the source, and come out smell'n like roses.

My wife's manual X3 has the 3.64 diffs and it a way better combo. You may lose some towing grunt, but honestly, unless your pulling stumps, uphill over a volcano or something crazy , I think you'll be fine for most mid to light towing applications.

Good Luck and let us know how it goes.

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2005 X5 3.0, 6MT, Alpine White on Truffle Brown, Sport, Preim, and Cold Weather, Alpina Stainless Headers, AFe Intake, UUC SSK, OEM 87's, 3.64 Differential Swap,Performance Modified Euro 2 Tune, UUC LTW Flywheel and HD clutch, Bilstein B12 Suspension kit
Future mods ZHP/Schrick Cam Shaft upgrade, Operation code name:Doppelschrauben-Kompressor

Wife's Ride: 2011 e70 X5 351 M///Sport.

Also in the fold: 2004 X3 3.0, 6MT, Black Sapphire on Terracotta, port, Premium, Cold Weather.