Lesion 760 cooling problem

Greetings all. Running a 2013 760. The "mechanism" that runs back and forth across radiator screen keeps stalling causing the obvious overheat. Thus machine has only 50 total hours. Our dealer is all over the problem but still.... All bearings and rollers are good. We have swapped the shut off valve from our other 760 also swapped the hydraulic motor. Same problem. Has anyone had this issue and if so what was the cure. Thanks

Lesion 760 cooling problem