Here's a photo of the Wheel Horse Wrench, the 11/8" head is thinner than a regular large wrench (1/4" vs 3/8"), that allows you to slide the head under the blade to fit on the hex bolt below the blade to lock/hold it in place, usually using the inside sides of the deck.
They were given out as a gift with a new tractor purchase, mid 70's - 90's (A, B, C, D-series and 200, 300, 400-series), and it has a part # too, they really do help a lot with the blade removal. A regular 11/8" open end wrench can be ground down to do the same, but then the 18" length is also a plus. I have seen them sold on eBay several years ago, not lately, but I guess if you have one, you'll keep and use it --- they also fit the large nuts for trailer ball hitches. I have my WH wrench in the tool box, that's where a lot of them probably still are. Rare, probably not, but hard to find, --- that's why I'ld look extra hard for it, in the prior owners tool boxes.
** Looks like the drive belt came off during transport, so the 'Mule Drive' can stay on and belt routing looks to be OK. To replace a belt, yes, the 'Mule Drive' assembly must be removed (using the 11/8" Wheel Horse wrench, again there) to route the belt correctly (like glgrumpy described).
In the above photo, I use the "dual-blade" system, with Gator Blades above the original standard blades so I have 12 cutting edges, and use a thinner 7/8" nut on the spindle threads. The Gator Blades keep the cuttings airborne to recut and give me much finer clippings and a greater throw, works with both RD and SD decks.
Edited by GlenPettit, June 16, 2014 - 06:49 PM.