I have a troybilt snowblower model 96177 going on 3 yrs old. When I went to remove
It from a neighbors basement it would not roll. It sat indoors through the summer so I can't imagine what could have happened.

Corrosion, i.e.. Rust in a damp basement likes to fuse parts together. A transmission, not in the right gear would also do it. Look carefully.

Mtd which acquired Troy-Built has manuals online, but yours comes up empty.

HELP FINDING YOUR PART (http://www.buymtdonline.com/webapp/wcs/stores/servlet/FindingYourPart_10101_19502_-1)

A diagram can work wonders.

If it's an MTD unit, find the model tag on the belly pan. This may be a unit that has about 6 or 7 gears under there, they had a tendency to freeze up (corrode) and not move. That drive has been replaced by a much simpler system using less than half that many gears. Check your model and then with MTD.