[xquatch]

cookiemontis thanks for that input. I was wondering if the 53BZ and the longer 45BZ would result in the same offset. I'm thinking that the longer variant of the 45BZ (M models) that I've installed is just a bit longer overall and preventing me from using my original driveshaft (1485mm). I tried every angle and contortion and nothing would give me the clearance to get both ends into mounting position.

I've sourced a 2007 335i (pre-LCI) driveshaft (335i AT @ 1453 mm) (PN 26107614433 or 26107558504) that should work. The next possibility might be the 335i N55 LCI AT driveshaft @ 1472mm (PN 26107574678).

I cleaned up the splines on the donor AT shaft that was slipping but that didn't work, still slips.