I noticed a lot of the trucks have transmissions that are geared for everyday use, how would one go about lowering the gear ratios on transmissions to suit rock crawling or mud running?
Just edit the gear ratios in the transmission section. Have a look at the .jbeam files - it's not too hard to work out how things can be modified.
Yeah, ten minutes of looking after I posted this I found it. Guess i didn't look hard enough the first time.