right - check ur chassis straightness as i said in my other post mate, and be sure to use a little thread lock on screws into metal parts. as for the hole near the flywheel, i just use some tape on both sides of the chassis to keep grit etc out.

i know i keep sayin this to people, but if u can get hold of the one piece chassis by JT Racing, then u will notice a whole load of difference in the reliability of all parts, due to the extra stiffness of it, it is made of a much stiffer alloy than the standard chassis. i havent stripped a spur gear since fitting it many months ago, and thats with an os18cvr in there, running on the beach...

nearly forgot - check that ur driveshaft cup right next to the brake, is clamping the shaft properly on the flat part of the shaft, i have had the same prob when i accidentally tightened it on the round part of the shaft - i hope that makes sense!!