Congratulations on a free Murray.
I have a cousin that got a geared transmission Murray dirt cheap at an auction because it couldn't be pushed in neutral. The auction admins. said the transmission may be bad. I put a bug in his ear that the brake was probably stuck and it was.
When they are old and we aged with them we find a way not to do maintenance down at dirt level anymore because it's difficult to get back up. Take care of them and they will last a long time.