My 2017 overheating pulling a 4,500 lb. Travel trailer. Never got hot on level ground but once I start up hill it overheats in less then 2 or 3 minutes. Watching Trans. Temp I notice it jumps up to 230 quick, but I never loose any coolest. Had it to the shop twice. It just started this . No dip stick to ck. Transmission oil level.