From what I know, it is. It could theoretically be changed to manual, but you (or someone else) would need access to Mudrunner's source code and a lot of coding experience to change the automatic refueling to manual, maybe with a way to switch back if something goes horribly wrong. Either that or an extremely complicated mod that overrides the automatic refueling system and uses a custom-made manual refueling system, either by injecting code or some other means.

SpinTires Plus could be an option. But dose it work still with the most current version and DLC

Originally posted by always glass0fjuice:

SpinTires Plus could be an option. But dose it work still with the most current version and DLC

works just fine
though, it may take some time finding SpinTires Plus version needed