If you go on pirate, or naxja, there is a mj owner on there, who has figured out the solenoids in the aw4, and has a wiring schematic, and info he will sell you to do just what you said.
The thing about running an auto, on the trail is you dont stall, but the bad thing is you have to trun som rpms at times, and once you clear an obstacle, if you letr off you sometimes lose momentum.
90 Comanche thing. Exo-cage, tube bed, with a few other things done Here is a link to some pics of it
If you have to ask why... Its a truggy thing and you wouldn't understand