A lot have asked for a How-to for this subject. I was doing mine today so I decided to make one. Enjoy.
Remove battery, tray, air intake and anything obstructing access to the top plate on the transmission.
Pull up on the shift cables, they pop right off. Move to the side.
I recommend removing the trans mount. Its one 1/2in mount bolt and it gives you room to wrench. Be sure to support it with a jack and a wood block, this will also aid you in lining up the trans mount to slide the long bolt back in.
Remove the seven 13mm bolts from the top plate. I use a gear wrench for this.
Note: The bolt under the counter weight will NOT come out of the plate. The idea here is to loosen it last and bring the plate up off the trans while rotating the bolt counterclockwise.
Cover the exposed transmission with a towel or something to prevent objects from falling into it.
Place your trans plate in a vice, or secure it somewhere you can bang on it and it won't move.
Using a punch and hammer, or mallet, remove the two pins in the shaft. They hold the shift selector on and the stock _____ (IDK what the OEM item the 3rd gear extender replaces is called)
Note the positions of the items before removing them.
Stock part on the left of the 3rd gear extender for comparison.
Clean the items with something, I used a "lint free" shop towel.
Re assemble the shift selector and 3rd gear extender onto the shaft and make sure the notches are properly aligned.
Install locking pins.
Clean the mating surfaces of the plate and the transmission. I use paint thinner and a wire brush. If you do this you MUST have a shop vac to remove any dust or debris you agitate on, in and around the open transmission.
Run a bead of Transmission sealant Mopar part # ________, or equivalent Anaerobic sealant. Failure to use the appropriate sealant may result in seal failure and corrosion.
I use this:
Install plate onto top of transmission. Note: I place the shift selector in the middle position to align the internals and make sure the forks are aligned to allow the selector to slide into them.
Begin tightening the bolt under the weight first. As you tighten each bolt periodically move the counterweight to ensure it moves freely and without restriction.
I can't fit a torque wrench in the bay there, so I tightened the bolts until I was confident they were tight enough. Some people use Loctite or Threadlock, that is acceptable, as long as the bolts are in fact tight.
Attempt to shift the car, engine off, into each gear. I have never had any problem not being able to do this after install.
I lost the end to my sealant, so that's the reason for my putty knife and fat ass bead. I cleaned it up before I put the plate in, so nothing dripped into the trans.
If anyone can help me fill in the blanks I will. All help is appreciated.
If in the process of installing a shift selector at the same time, and you break the roll pin, it can be ordered here
It is part number 6101475