92 GQ gearbox mounts

Like most GQ owners mine has that knocking noise.
I have just had both engine mounts relaced (both broken) and took it out yesterday thinking the knock would be cured but no!!!!!!! I sounds like it is coming from the gearbox area. I have just been outside putting a little pressure on the gearbox with a bottle jack to see if the gearbox mounts have also split but it is hard to tell, it looks as if there is movement at the mounts but I don't know how much there should be, would I be best removing the tailshaft then jacking it up.
If the gearbox mounts are broken would it give a Knocking noise and what is the procedure for replacing them(can't see any diagrams in gregorys manual)
The most obvious answer is the body mounts but they have all been replaced when I did the body lift.

Any help would be gratly appreciated

Mark. (1992 4.2efi GQ)