I swaped out the auto trans in my roadrunner for a a833 4 speed setup. I used the same driveshaft from the auto and the correct year manual trans cross member. I now have a very bad vibration at anything 60mph or over. If i press the clutch in when it vibrates no change.

I did notice that my drive shaft is pushed into the tail housing almost all the way to the yoke. Could this be the problem?