john deere lx188 drive belt

lx188 drive belt has problems staying on, new belt and new pulleys runs great for some time then comes off, owner said this last time there was a grinding noise then no mower movement. any suggestion's as to what could be the problem.
thanks
AC

Suggestion start the mower and listen as to where the grinding noise is coming from. It would be either one of the new pulleys or the hydrostatic transaxle. Noise should go away where the clutch/brake is depressed. Got to use your ears as we are not there to hold your hand.

MY Crystal was sent out for service and USPS lost it.

Hello A.,
Are you referring to the traction drive belt or the deck blade drive belt?

traction