Small Engines (Lawn Mowers, etc.): Yard Machine Drive Belt

Question
42 inch 18 hp...trying to replace transmission belt...The drive pulley is located too close to the frame to get the belt onto the pulley...when I tried to remove the pulley retaining nut it torqued against the transmisdion and the wheels rolled...I was afraid to bear down too hard....is there a trick to getting the belt onto the pulley or an easy way to remove the pulley nut?
Thanks

Answer
What is the mower model number?  The model number is on a sticker, about the size of a business card, and will be in a format similar to xxx-xxx-xxx or xxxxxxxxxx.

As far as a trick to remove the pulley nut, and air impact gun is the trick.

An alternative trick you can use is to loosen the transaxle bolts and jack the mower up allowing the transmission to drop just a little to install the belt.  Sometimes you can even remove a couple of the bolts allowing the transaxle to drop a little and tilt as well.

Let me know the mower model.

Eric