I have a John Deere 1020 Gas that died while driving it home. It has been sitting in a shed for more then 10 years. It ran fine for about 6 to 7 miles then just slowly came to stop. Tried to crank it over and it wont do anything but clunk. I thought maybe the hydraulic pump locked up but I took the coupler apart and that wasn't it. Motor still will not turn over. Now I am thinking something in the transmission has it locked up. Any ideas would be greatly appreciated! Thank you