yeah my giga crusher is having a similar problem, i had the servo out and after putting it back they are pretty rubbish, after much screwing around ive got them to work sort of, well it flips end over end if i stonk on them at high speed lol but they work alot better if i move it by hand, so i might get another servo or take it somewhere to get set up better since i'm a n00b haha, stripped the gears in my steering servo the other day thought screw it and bought one with metal gears, awesome now, but yeah i might change all of them.

i think most of the reason i stripped my servo gears was too much tarmac use with big tyres and a 3kg standard servo, now i have a 10 kg, the aim is not to smack it into curbs too lol, neighbours arn't too happy with me LOL