Small Engines (Lawn Mowers, etc.): MTD Transmission Drive Belts, electric clutch, engine shaft

Question
Ben, I have a MTD Yard Machine 6-speed Shift-On-The-Go 38" Twin Blade Deck. Model 13AC762F729, Ser 1C166B70388. Date of Manuf 03/2006, but just beginning second season of use. I have a large, flat yard, and it has worked fine last 2 weekends. Yesterday, upon first starting, it cut grass fine. I noticed that it did not have any fast speed. Only moved slow and detected engine was running a tiny bit odd. Checked everything I could, but didn't see a problem. Kept mowing and after a few minutes, smelled something like burning. Found that the drive belt 754-04001A was shredded and strings of it hanging all around with small chunks and strings of it laying on top of blade deck. The belt was barely still on. I snipped it off. I am assuming that was the problem for slow movement, but I am concerned what could have caused a relatively new belt to shred? Could there be something to be checked in that regard? Anyway, I bought the belt locally and was able to get one end on the engine shaft pulley, but when looking at the transmission area, I cannot figure out how in the world to get it on the trans pulley above the smaller trans belt (754-0241A). I would also like to go ahead and change that belt, too, while I'm in there, if you can tell me how to change them both.
Thanks,
Dave

Answer
Dave
Is this a Model #760–779
What may have happened is the belt was properly aligned  with the pulley in that case you would get uneven wear real fast. Did you hit anything or was the deck not level does thing will tear up a belt fast,Also  check to see if the clutch is not defective. This clutch is the electric clutch on the bottom of the engine shaft,it has 2 wires going to it make sure before you put the belt on that it spins freely. To change the trans axle belt you need to do it from the top their is a small amount of room to get it on but it will go on. Watch out for your knuckles, Now you may understand what we have too go thru,

IMPORTANT: For a proper
working machine, use
Factory Approved Parts.
V-belts are designed to
engage and disengage
safely. A substitute (non
OEM) V-belt can be
dangerous by not
disengaging completely.