Trying to figure out a noise/vibration - E82 128i

JoeTR6 said:

At this point, I'd be tempted to swap the drivetrain into a different chassis, say a 2002.  If the vibration goes away, roll the E82 off a cliff and be done with it.  Frustrating to say the least.

Don't think you're the first to have considered the cliff option.

As for transplanting into my 2002, that's a hard no. I love my simple M10/4 speed setup and have no intention of replacing it. If you were inclined to drop an N52 into a TR6, well, they're good engines, readily available, and fairly cheap.

As I type this, I feel like I'm in some sort of weird dream (and I might be, in which case I'm going to be really pissed when I wake up), but I believe the problem is fixed.

I installed replacement driveshaft #2 this morning (they overnighted it from NV to NY, much to my surprise). Test drive shows very, very minor vibration at, um, full highway speed; what vibration remains may just be a function of other factors, but whatever it is, it's a miniscule fraction of what there was before, so I'm good with it.

Even before I installed it, I was pleased that to find that replacement driveshaft #2 differed from replacement #1 in that the latter had Spicer U-joints with grease fittings, while #1 had unbranded U-joints with no grease fittings. Probably a supply issue, but whatever the case, I'd rather have the greaseable Spicer parts in there.

Thanks for all the suggestions and commiseration along the way. To say this has been an odyssey is putting it mildly, and I'm glad to see the back of it.

Congrats!