A common problem: GEMS throttle hesitation and rumbling
The problem of D1's having the rumbling and throttle hesitation (especially at highway speeds) seems to be talked about a lot here. I have had this problem in all my GEMS rovers and I found this site very helpful.
http://www.fourfold.org/LR_FAQ/Disco...e.Problem.html
"Out of every one hundred men, ten should not even be there, eighty are just targets, nine are the real fighters, and we are lucky to have them for they make the battle. Ah, but the one, one is a warrior, and he will bring the others back"