The other day took my truck on the freeway and when I got up to speed noticed a vibration. Try to decribe it. Pretty hard vibration gear shift clutch pedal. I know it has nothing to do with tires balancing, when I push clutch in going about 65 the noise and viration goes away. Would the flywheel cause such a vibration. Like I stated when you push clutch in it goes away at 65 the steering has no vibration so it can be somthing in the drivetrain? It does have a 3inch body lift, and for some reason there was a couple of tranny mounts not put on. Could this be the problem. Driving around town and in the hills no problem.

If this is a stock tranny and t-case there is only one mount. If you mean the bolts that hold the mount to the t-case and x-member and the x-member to the frame, replace them.