I have a Bronco and any time I drive at a high rpm it throws the top belt. I replaced the belt when I noticed a chunk missing thinking that was the problem but it continues to throw the belt. Only happens at high rpm when pedal is fully engaged. Any suggestions?

Hi,
You did not supply the model number, but there is one thing that invariably causes MTD products to throw belts. The transaxle is fastened by two bolts at each side at the axle housing. Somewhere else further toward the front are one or two bolts (depending on the exact model) that keep the whole unit in line and not twisting from the torque. These stay bolt(s) are missing.
Peace,
Clarke