driveshaft

I recently replaced my 2 piece driveshaft with a 1 piece steel driveshaft. Afterwards I noticed a vibration between 50 and 60mph. The driveshaft came with a new yoke, new u-joints, and should have already been balanced. I took the car to my mechanic and he said he couldn't find anything else...

87 Mk3 Supra, built 7mgte I went on Dyno last october. Made 340 lbs torque at 4500 rpm. Above that, clutch slips...(spec stage 3...) Motor is strong, has everything it needs. This winter I'm making sure this won't happen again. Dyno guy offer me Competion clutch Stage 4. First question...

Will the front shaft of a r154 driveshaft fit into a w58 transmission? And if so can rhe r154 front shaft bolt on to the rear shaft of an auto a340e driveshaft? (I'm working on a 5 speed swap, picked up what I thought was a w58 driveshaft but turned out to be the r154) :1zhelp::1zhelp:

ok first off i know a lot of people are gonna say get a one pc. drive shaft but im broke right now and just want the bad bearing switched. so i found out my center support was bad and decided to buy a new one i got prices and they were more then i had so i got the part number on line and ordered...