So it only happens when I'm taking a turn and downshifting...

this LOUD and ABRUBT noise comes from my transmission area. Sounds almost like the car is going to break in half and it's coming from directly under my shifter area... so the first thing I think is a broken tranny mount.

I jack the car up and get underneath to take a look around... everything seems fine... trannsmission mounts all appear to be ok... but the driveshaft is real close to the tunnel and i notice a bolt that extends threw the emergency brake cable point that's touching the driveshaft. You can see that it's definatly hitting the driveshaft in the picture b/c it's leaving marks...

What would cause my driveshaft out be out of wack like that...???

The transmission and mount is stock,

Also the driveshaft has some play in it.. is that normal...??

 

First I'd examine the whole engine+tranny placement in the bay. Then if it all looked correct to me, I'd trim that little doodad and call it good.

The play you mention is most likely in the rear end. Try to look for play in the u-joints themselves.

 

Definately check them U-joints,thats not a pretty looking driveline and the U-joint failure is pretty common on older cars like ours.If need be,pull off the driveline and give both ends a good rock-around to feel for binding and roughness in the joints.

 

it doesn't seem to me like there's anything wrong with the u-joints themselves, it looks like things are just out of alignment. I would go about checking motor mounts and tranny mounts for slop. grab the the intake manifold and rock the engine.

 

After looking around I'm going to say that the motor mount brace is the cause.

It's a 12A mount that I re-welded / positioned to fit a 13B and it looks as if it slightly favors the left.

 

Actually the motor mount brace favors the right (only by prob an inch, maybe even less) causing the transmission to favor the left, therefore rubbing the nut pictured above. I cut the threads of the nut off, which fixed the rubbing on the driveshaft and the loud noise...

but then it also caused this: https://www.rx7club.com/1st-generation-specific-1979-1985-18/bad-transmssion-mount-716514/

I replaced the transmission mount and when I was removing the two nuts that hold the mount to the transmission, I couldn't even get the wrench on the left nut being it was so fa'cocked towards the left side.

Time to get a new motor mount brace.