I actually did get an e-mail response with a manual in pdf and that will be useful to me. However, my model # is actually 465612X99B. It is a 2001 model and, after pulling and fixing a rear tire that was off the rim, it won't drive! We just moved it prior to this repair and had to muscle it into a truck bed on ramps. I worried we may damaged the transaxle. I see that a square key is often required and I did not notice one but didn't know to look for one. I hoped to get a manual for guidance for this and all the other issues that may arise!

Hi,
Yes the key is 5/32" square x 2" long and is required to hook the rim to the axle. I will look for you manual.
Peace,
Clarke

Hi,
Well, more than one thing, I once again separated your post for clarity. Your mower is covered in a CPSC recall because some gas tanks split(so keep an eye in it!)
Lastly I found no owners manual, but did find the pdf parts breakdown at:
http://www.outdoordistributors.com/pdf/Murray/MURRAY-MODEL-465612X99B-LAWN-TRACTOR-(2001)-PARTS-LIST.pdf
Peace,
Clarke

Post some pics
And ill see if my is the samething