I recently purchased a dynahoe 140AD with a 3-53 Detroit diesel. Put new brakes on it first then went out to the dirt to start my projects. It was running great and digging great then after about 4 hours of digging it stopped running like it ran out of fuel. My son was operating it at the time so he put more fuel in and swent to bleeding the air out of the system. After 2 days of troubleshooting we found that the top end of the motor wasnt moving when cranking it over. Valve springs push rods etc no movement whatsoever. Not good! Also, the fuel pump drive rod wasnt moving so it definitely couldnt pump fuel. Further inspection found timing chain was ok but on the back of the motor we got our hands in tight spot against the firewall and popped off a few covers of what Im told is the accessory drive. Stuck our fingers in there and found at lease 1 gear with missing teeth. This is where i stop, I need a mechanic to fix this 3-53 but havent been able to find one that has the time. I dont have the capability to pull the engine myself and try to check it out further. Does anyone have any ideas what could have happened??