Here is Jerry's write up. I saved it from a LONG time ago:
Here's a write-up on changing the shifter from under the car.
Removing the shifter
1. Put the car on jack stands with the frame about 17 in. off the floor.
2. Remove the frame plate under the transmission by removing all 12 of the attachment bolts with a 19/32 or 15mm socket.
3. Put the shifter in neutral and keep it there during this whole procedure. Remove the shifter knob from the shifter stud from inside the car with a 3/4 open end wrench. Now remove the stud. If you have the original shifter stud with the shock mounting isolator, the stud will be easier removed from under the car with a 3/4 or 19 mm open end wrench, after you have performed item 5. If you have the aftermarket SVSI solid stud, remove it now (before lowering the transmission), from the inside of the car. Simply push down on the shifter boot and unscrew it with a 9/16 open end wrench, and pull it out of the boot. If you have aftermarket throttle body intake tubes, loosen them on one end so that when you drop the rear of the transmission they will not be damaged when pulled away from the air box.
4. Put a jack under the rear of the transmission just in front of the crossmember support, then remove the two crossmember bolts that hold the rear of the transmission. Use a 15 mm socket and a 15 mm open end wrench.
5. After the bolts are removed, lower the jack so that the trany comes down a little more than 1 in. at the bolts.
6. Reach up over the top of the rear part of the transmission to locate by feel the four bolts that hold the shifter to the top of the transmission. Use a 13 mm open end wrench to remove these four bolts. Be careful that you do not remove the wrong two bolts that are forward of these four bolts and the same size. The space is tight in this area, but after a little practice it is not that difficult. The two forward bolts are the most difficult, but if you take small movements of the wrench with the length of the wrench forward and turning the wrench over after each movement, you will be able to remove these bolts. You may find it helpful to unclip some of the wiring harnesses in the tunnel and push them aside, to get more room. The amount of room depends on how far the trany comes down. On my car with aftermarket tri-y headers, it only came down 1 inch. With stock headers, the trany may come down 1 1/2 in..
7. The shifter probably is sealed to the trany with RTV sealer, so you may have to pry on it to get the shifter to come loose. When loose, lift vertically, then move it around to get it to come out of the small space. The ball end of the shifter fits into a plastic bushing that may come out with the shifter. Make sure that you put this bushing back into the trany into its pocket. You will feel the hole where it should be located.
Reinstalling the shifter
1. Put the stock rubber boot seal back on shifter if you have removed it for any reason. Work the shifter around (without the shifter stud), until you get it to go back into the small space and on top of the trany. Make sure that you have the plastic bushing in place. Before putting in the bolts, raise the shifter slightly and apply with your finger a thin coat of RTV sealer to the rim of the mounting surface of the trany. I used Permatex Ultra Copper (red in color), but any high temperature RTV will work. This is necessary since there is some free oil in this shifter box. Now put in the four bolts and tighten them down. I did not use Locktite on the four bolts, since it makes it too hard to remove a second time if necessary.
2. If you are installing the stock shock mounted shifter stud, replace it as you removed it, from under the car. If you are installing an aftermarket solid stud, you can install this one from inside the car after step 3.
3. Now re-clip the wire harnesses that you may have unclipped. Jack up the trany and reinstall the two crossmember bolts. Replace the frame plate with the turned down lip at the front, and torque all 12 of these bolts to 30 ft. lbs. starting from the center and working outward.
4. If you have an after market shifter stud to install, go inside the car and push the shifter boot down until you see the shifter arm. Put in the shifter stud with blue 242 Locktite on the arm of the shifter. Make sure that you thread the metric thread into the shifter and not the 1/2-20 thread which is for the knob. SVSi makes a solid shifter bolt that is 3 1/2 in. long if you want to replace the stock shock stud. The cost of the longer stud was around $10. Put on the shifter knob of your choice. Now reconnect the throttle body intake tubes where they were disconnected, and you are
done.
