So I ask again, since this doesn't show a diagram for the PCU from a 4.0 I'm assuming there is no need for one? And - With this set up you can just leave it to be in drive and not constantly needing to shift?
One other thing to understand, you STILL need a floor shifter with this setup. The floor shifter will control your MAXIMUM gear that you can shift to using the rail shifter when you are in manual mode. The rail shifter will shift gears but cannot put the transmission INTO gear, if that makes sense. You use the floor shifter for that.
So, as an example, if I'm on the dunes, I usually leave the floor shifter in third gear and then with the switch flipped to manual control, I can use the shifter to go between 1st, 2nd and 3rd however I want. I CANNOT go into fourth without moving the floor shifter. This also gives me third gear engine braking. If I want second or first gear engine braking, I have to shift the floor shifter into those.
It might sound complicated, but you really set the floor shifter once for whatever you're doing (offroad trails I'm much more likely to leave the floor shifter in 2nd, for example). In those moments where you want to add engine braking at a lower gear, it's simple to knock the floor shifter down.
Reading all of that back it does sound very complicated, but it's really, really not.
Edit to add one more note: for the power feed to the rail shifter, pick a switched positive. Somehow I didn't and if I leave the switch in Manual mode with the shifter in one of the three solenoids "ON" I get a battery drain. I got in the habit of checking the switch as I get out of the Jeep so it's not been an issue, but I drained the battery a couple times doing that by mistake. I plan to correct that with my current rewire.
