Just purchased a 70 442 with a 4 speed. Driving it from the delivery truck I noticed 4th gear wanted to pop out and a noise (rotational) coming from the tranny tunnel when the suspension went up and down. When I looked under the car! the linkage is jammed up against the top of the tranny tunnel and there are clear indications of the drive shaft u-joint knuckles hitting the top of the tunnel.
I noticed the rubber mount between the transmission cross member and the transmission appears to be very high. Does anyone know what the height of that mount is supposed to be? Would it make any difference if Installed one half the height of the this one? I attached a pic of the bracket.

Any comments will be appreciated.

 

Seems to me like that happened on the '69 Cutlass I worked on a while back, or perhaps the '66. It may have been solved by replacing the body mounts, I don't recall. Shorter trans mount is the obvious solution.

 

or the motor mount is collapsed

 

It is you transmission mount. They put a polyurethane bushing in there. I have yet to see one of them the correct height. Get you a good rubber one and it should fix your problem... or at least most of it providing they didn't do something else that is contributing to it.

 

While I agree that a correct rubber mount will likely fix this, be sure to check the flanges on the frame rails where the crossmember mounts. I had a similar problem on my 70 W-30. Come to find out that an idiot previous owner had jacked the car under the open section of the frame rails, bending the lower flange upward, Naturally, this pushed the crossmember and trans closer to the floorboard.

 

Thanks for the tips. Will try and find a mount that is half the height after checking the motor mounts and crossmember.