2007 GMC T7500 T7F042 6 Cyl 7.80L
Hit a bump and engine light 2/3 power
Not only that. Brake and emergency brake light will go on and constantly beep. Shut off and on and it's gone. Does it a lot. Loaded 5000 lbs. going uphill truck overheats. Shut off for 3 minutes and it's all good. Top up antifreeze 2-3 inches and it doesn't happen. Week later all over again. Help!!