Figured out a way to keep my drive belt from jumping off on my hustler raptor. I noticed the black plastic fans above my transmissions were bent upward towards the drive belt, dealer said solution to that was to replace, that means you’re in for a lot of labor and he said that’s all you could do, I beg to differ, I took my heat gun and heated each plastic blade on both fans one blade at a time and then I would hold downward on the blade with a cool wet rag until blade cooled in place, it worked, now the blades are more downward like they should be and no longer upward pushing my belt off
Check the hydro mounting brackets to see if they are broken and or the mounting bolts are loose or missing. If the brackets are bent or broken the make a bracket kit to correct the problem. New brackets are much heavier.
I have posted this multiple times. If your throwing belts check that your mower has the correct Hydro braces installed and that all the bolts are tight. Here is a picture with part numbers and EVERY Raptor should have these upgraded brackets if your machine did not come with them. Very simple to install and it will eliminate your problems.