.
I'm actually in the process of installing one now.
Saw Extreme Terrain selling one for $47 that looked like they stole it off a kids bike.
So I found these on Amazon. Shimano 6 speed shifter and Corki cable.
First problem was the diameter of the jeep shift lever vs the clamp size.
The Shimano gave 22 mm as the I.D. of the clamp. So I dig around in my tool box and found an old garage sale deep socket. I tapped the socket to a 10 x 1.5 thread to match the jeep shift lever.
I removed the shift knob and jam nut.
Installed the socket and Shimano shifter.
Then installed the shift knob, using the socket as a jam nut.
I checked the length of throw for the shifter. It's less than an inch. Roughly 7/8"-15/16".
I checked the throttle and 1" takes the idle up past 2,000 so that should be enough.
What I need to do now is thread the cable down through the shift boot, along side the transmission and back up to the throttle lever with the least amount of sharp turns.
Here's where I am so far...
Shimano Shifter
$13.99
THALOUS Bike Shifter SL-TX30-6R/7R 6/7 Speed Right Thumb Gear Shift Lever for MTB Mountain Bicycle
https://www.amazon.com/gp/aw/d/B0BGSX1NRB?psc=1&ref=ppx_pop_mob_b_asin_title
Corki Universal Bicycle Shifter Cable Housing Set for Shimano Sram Derailleu
$11.49
https://www.amazon.com/gp/aw/d/B07JLWSF82?psc=1&ref=ppx_pop_mob_b_asin_title