ORIGINAL: phmaximus
do u have a friend to test it on a lipo?
That brings up another possibility. The esc(electronic speed control) may be set up for lipo type batteries instead of nimh and nicad batteries. Nimh and nicad batteries drop to a lower voltage than lipos when they are under load. This may have activated the low voltage cutoff the esc has while in lipo mode. I would check your manual and make sure the esc isn't set for lipos.