Small Engines (Lawn Mowers, etc.): Mower wont roll all the time., rear fender, hp motor

Question
I have Murray MDT riding mower. I believe it’s around a 2004 with 42” deck and 12 hp motor. For some reason, when it sits for a short period, the rear end or differential seem to lock up and the mower won’t roll. If I rock it back and forth, it seems to eventually start to move. Is there oil or grease to change or fill up in the differential? Thanks for your time.

Answer
I need the mower model number to see which transmission you have.  The mower model number is located on a sticker, about the size of a business card, usually found under the seat or rear fender.

Let me know the model number so I can look up your transmission.

Eric