Small Engines (Lawn Mowers, etc.): Murray Lawn Mower Gear Adjustment, lawn mower, model number

Question
I have a Murray Riding Lawn Mower, all the gears ar off by one gear and reverse does not work at all.  Do I need to get a new belt, or is there an adjustment that I could use that would allow the gears to work properly?

Answer
There should be a bolt that holds the shifter lever to the transmission.  Is it tight? The lever bracket is square cut, I believe; if the bolt is loose the bracket may not be on correctly.

What brand of transmission do you have?  There should be a metal plate on the transmission with the model number.

Let me know.
Eric