4500 Ford Industrial Backhoe/Loader

Hello New to the forums and I am looking for information on 4500 ford industrial backhoe with the shuttle shift type transmission. We have had this hoe for about 3 years now. It does not get used much. The first year we had it is when it got the most use. She starts great and runs strong. The hoe works as advertised and so does the loader. the issue we are having now is we run it for about 45 minutes and all of a sudden it will not move forward or backward in any gear. You shut it down and let it sit for 30 minutes and you can run it again. I have changed fluids twice and filters it seems to help a bit meaning you can get about another 1/2 hour operating before it starts that cycle. I was thinking of pulling the radiator and trans-cooler next to ensure they are clear. The temperature light does not come on but I have not checked the sensor to ensure its operational. Any insight or thoughts would be appreciated

I'm not familiar with fords, so this is general advice, take it for what it is.

Get a temperature gun / infrared thermometer and take the temps going into and out of the trans cooler, and the transmission when it's operating normally and when it's acting up, or just feel them if you can judge temp.

If it's not overheating the oil, then I'd get to know the system and see if there's any rubber hoses collapsing on the suction side of the transmission. Any air leaks on the suction side could do something like this too. Usually this would be internal to a transmission, but I don't know.

Are you operating it in too high a gear for the work you're doing? If it's getting hot, try the next lower gear to let the engine and trans run faster and slip less.

Thanks Delmer I appreciate that and will look into the temps. I do have a hand held temp gauge and can check that on both ends. I also read about a pressure port on the bottom that I plan to hook up gauge to and monitor it that way as well.