Cutting the notch for the transmission plug.
It is necessary to cut a notch in the frame for the transmission plug. While there is no clearance problem with the transmission itself, it is impossible to plug the main harness into the transmission without notching the frame rail to get access clearance.
As you can see, the plug sits ~1/4" from the frame rail, no possible way to get a 1" plug on it... SO... we must cut.
You don't need to lift the transmission into place like I did to mark where you need to cut, just bolt the crossmember into place and measure 2.5 inches back, and 2.5 inches from the frame rail. That is the box you will need to cut.
The transmission tunnel rail is formed with VERY VERY strong steel. It is not pleasant to cut, to say the least. I did it with a combination of die grinder with cutoff wheels, an air hammer with chisel, and an angle grinder. IDEALLY you would use either an acetylene torch or a plasma cutter on a lift. (Be careful not to catch your carpet on fire if you use those two). However, either will work.
Also note, there are two seperate layers of the rail, and you will have to cut through them both.
Here's a view, halfway cut.
Another view, with the inner rail also cut out.
Once you have your cutout, you are finished as far as clearance for the transmission. Structurally, I think the car would be fine. HOWEVER, you are compromising the integrity of the transmission tunnel by trimming the rail in this fashion. For that reason, I
HIGHLY RECOMMEND you take your car to a muffler shop, chassis shop, or speed shop, to have the hole you cut boxed/welded with plate steel, to reintroduce some strength back to it. (Or if you can weld, and have a welder accessible, go ahead and do it now.) Better safe then sorry.
Now we move onto the transmission cooler, the last step before we install the trans/tc/driveshaft.