After an 800+mile road trip last weekend in my new-to-me E53 M54 manual I realized this thing is NOT geared for highway driving. 5th is 1-1, not overdrive, so at 80mph I'm turning almost 4,000rpm with that 4.10 final drive.

Is a diff gear swap possible, and would it be possible to disconnect the front diff and driveshaft? I don't need AWD here and have no plans to off-road this beast other than basic dirt/gravel roads.

I suppose another option would be a gearbox swap from a post-LCI E53 6-speed, but unless there's another box that will fit there's probably fewer of those left than pre-LCI 5-speeds, if that box is specific to the E53 in general. I have no idea.

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