As the title says... This could be used for towing and etc where you don't want it hunting for gears. Useful for having one position that does one gear instead of M mode, which uses up lots of spots on the gear shifter.
You can do that already I believe. It does required addition of LUA to your mod, but you can define pretty much any pattern. I have done it in my T75 drifter mod, it might be now even easier to do. Attached file I had in semi/lua/controller but I should really rework that so that it would be in separate folder and just define custom controller in semi.jbeam or whatever will be main jbeam. You can check from wiki about custom controllers, I think there was some useful bits there too.
seems rather easy actually, but do i need to write a line of code on the transmission code to call my custom lua code? It's just sitting there in the mod folder not being read. If you have a copy of the engine.jbeam of the T series mod that would be great, i don't know what to put in there for my mod.
First a disclaimer: Zip is real dump, sorry about it, but I haven't really got around to put things into correct folders and haven't even had time to verify how everything works in 0.12, but it is my WIP folder of semi stuff which does includes parts that might be helpful to you. Also I'm not sure if there is parts from some other mods, so beware it is only for reference and can break the game. Lot of this is to help you find the answer, problem is that right now I don't remember how I did a lot of that, so sorry it will be a messy ride. That aside, you might find lua and how I have been calling lua from files, even this was done before new possibilities that will make it even easier I believe. I have not tested, but vehicle controller line should point to your own controller with own name, it should be possible now, before I had to replace whole default controller thing. I did try to document pain of making custom input control for splitter box here, it might have some useful bits too for how this lua stuff works: https://www.beamng.com/threads/failing-at-creating-custom-inputmap.51839/#post-783327 So there probably is no straight answer, but more of hints where to find answer, however that is better than nothing I hope!