Hey I need help, I recently swapped my 1995 cab, motor, and trans (longbed) over to a 1994 frame and rear end(shortbed). The rear end went from a 7.5” 3.73 to an 8.8” ls 3.55.
I had to swap the front u joint and yoke from my driveshaft over to the shortbed driveshaft as it had an A4ld and the yoke didn’t fit an m5r1.

now I have a really bad vibration. It shakes everything from the shifter to the pedals. I thought it was bad alignment (I installed the steering shaft in the wrong rotation.) but not I’m thinking it’s maybe the driveshaft…
The only thing I know is, when I installed the driveshaft, it looked like it didn’t fit into the trans the way it should have.
can someone give me an idea of what might be vibrating?

 

did you ever get your issue resolved ? My first thought was driveshaft out of Balance

 

I thought U-joints out of phase.