What Stopped My Toro?

Last evening my son Tim was about to cut the lawn but every time he engaged the drive on the lawn tractor, there was a loud vibration and a terrible, pulsing noise coming from the rear trans axle.  The grass really needed cutting but it sounded like the tractor would not make it through the job. What ever it was, it sounded expensive. Looking from underneath I could see that the drive belt was fluttering wildly whenever he engaged it. I have all the service manuals for this machine on my computer so I checked out how to replace the drive belt (not a 10 minute job) and searched for the part number. I figured the belt must be ready to break and was vibrating because of a tear or gouge.  Tim finished the lawn without a further event, so, since it was dark now,  I  decide to tackle the repair in the morning.

I ran the tractor up on the ramps and followed the instructions in the service manual for changing the main drive belt. With the rear cover removed I defeated the safety cut-out so I could see (while engaging) the trans-axle pulley and the pulsating belt. Normally the belt will not engage without the driver sitting in the seat, but you can insert a jumper wire in the interlock and bypass this safety feature. I started and stopped it a few times but I could see nothing wrong with the belt or the pulleys.

Then, just by luck, when I turned the engine off, the pulley stopped and I could see a bulge in the belt. This, I thought confirmed my feeling that the belt was defective and I was about to go in and call the Toro dealer. While I had it apart I cleaned all the grass fluff and debris off the trans-axle and fan so It should run cooler now

I twisted the belt as if to pull it off the pulley and  lo and behold, there was some small pieces of wood stuck in the groove of the trans-axle pulley. I can't imagine that you could ever get anything to stay wedged in the pulley even if you tried. It took a fair effort with a small screwdriver to dislodge the chips.

Problem solved - Cost $0.

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