'87 740 turbo sedab

Having a bit of low frequency noise through frame when the car is loaded in the back. Suspect the mounts.
Motor mounts look okay.

Clearance between oil pan and crossmember is about 1/16". What is normal?

From inside the car (at the manual shift stick) tranny looks like it rides a bit low. Also bounces a little when I hit rolling bumps on the road.

I got under the car to inspect the tranny mount. Seems like some oil has leaked on to it at some point in it lifetime...I know that this will degrade the rubber.

There is a circular-shaped metal part (like the end of a trumpet horn) which extends out the bottom of the mount, below the cross memeber. How far should this be below the cross member? I am trying to use this as a guage of how over-compressed the mount may be due to spongy rubber.

Cheers