This may seem like a dumb question but I'm going to ask it anyway.
How important is it to reinstall the drive shaft exactly as it came off? Everything I've read says to mark the yoke and shaft so you put it back the same way. What if you rotated it 180deg when you put it back? Will that destroy something?
I've had my front DS off 3x now and it's never been marked any time we've taken it off. I'm getting a spinning/spooling up noise when I accelerate and I'm wondering if rotating the DS 180 has thrown off the balance or something.

 

I wouldnt think it would matter. A balanced shaft is most important. I never mark mine.

 

Did this noise start right after you put your shaft back in?

 

The drive shaft is a balanced unit, probably just time for a rebuild.

 

Sort of. The noise started after I replaced my transfer case. The front output on the new TC has a little play so it may be bad bearings.
It sounds like it's coming from further forward though. I can only hear it in the cab. I can't hear it any better with the windows down.

I just wondered if putting the drive shaft on wrong had damaged the pinion bearings in the front diff, or if it had damaged the bearings on the front output of the TC.

I wonder though, why everything says to mark the yoke if it doesn't matter.

Oh, all U joints on the drive shaft were replaced, so it's not that. Also new U joints and bearing hubs on the front axle.