Ok sorry about the quick post yesterday i was at my wits end with this vibration It is a 1980 RX-7 withthe motor and trans out of a 1985 gs.
Just did motor swap and emmision removal about 2 mo. ago. Along with carb mod.. But I went thru the wheel bearing and they were all good. I got another driveshaftbut flange is bigger. need to know how to swap the mounting flange off driveline

 

The U-joints are not replaceable therefor the flange is not removable.

 

like IanS said, the yolk of the shaft is not meant to be interchangable, if thats what you are talking about.

 

I'm rebuilding my 87 TII. I found out the same thing about not being rebuildable. I took the driveshaft down to a driveshaft specialist and they put new greasable u-joints for me. If they ever need replacement, I will still have to take it down to be done. But $100 is better than $300+ for a new one.