Hello, I need help troubleshooting a 2009 Gehl 6640, Tandem pump, hi and lo flow, duetz engine. This machine was bought at auction and I have been working on getting it running correctly. It was full of dirt and heavily leaking hydraulics, so far I've cleaned it out, taken out the dual hydraulic pump and had it resealed, added OTTs from Mclaren, it's a beast now only leak I can find is in one of the drive motors, but it is minor. The engine temp gauge on the panel does not work, but it seems to run ok. The problem I have is when I am leveling an area I get about 4-5 scoops of dirt carried to a pile 50-60 feet away before the hydraulic overheat light illuminates and alarm sounds and I have to shut down and let it cool. If I am working in the woods, not running as hard, it takes a bit longer but usually ends up overheating. I cleaned out the oil cooler with a pressure wash and some degreaser. I don't know what else to check, could the main relief valve be off? I'm not sure how to check/adjust it? How do I tell if the oil cooler is bad? what should the input and output temp difference be when read with a temp gun on the outside of the hose? any ideas would help, there are no gehl certified mechanics near me. Thanks!