HI, I have a 6 speed Craftsman riding lawnmower model # 917.270532. It's an older mower that was given to me by my father in law so I would like to repair it rather than replace it. It has been a good mower until recently. I was mowing the lawn and everything was going perfect. Before finishing the job the mower started making a loud grinding sound while making a left turn. Going straight and making right turns was fine with no noise but the grinding continued on each left turn. I started to return the lawnmower to the storage area. Once I started going up a very small hill the mower stopped pulling. With the engine running and transmission in gear I managed to push the mower up the hill and parked it. I thought it was the gears in the transmission so I removed the transmission. I opened the top cover to look inside and everything looked great, no stripped gears, that I can tell, and no metal shavings in the transmission. Turning the gears by hand, they all seem to work fine although this way they are not under a load. With the transmission assembled you can turn the pulley on top of the transmission and the wheels starts to spin however, while turning the pulley with one hand you can hold the axle with the other hand and prevent it from spinning. All the pulleys spins freely ,by hand, with no unusual noise. Would a worn drive belt cause this problem? I once had the blade belt go bad and the mower acted like it had a bent blade, the whole mower vibrated and was noisy. I couldn't believe a belt would cause the mower to vibrate so bad but after replacing the belt it all worked as it should. Any suggestions or advice would be greatly appreciated. Thanks