I have a 2001 3500 diesel, auto tranny that started overheating with the plow up on the last snow. It has NEVER done this in the past and as far as I can tell, nothing has changed. The radiator is full, the tranny is full and both are clean. It does not go much past the upper normal limit but I have plowed the same way for 8yrs with this setup and I have never had the temp go beyond the lower normal limit with the plow up. Any ideas/suggestions as to what I should look for to correct this? My initial thought is the fan clutch that may not locking in when the temp starts to rise. Any info will be helpful.
I would start with the front of the rad and look for something blocking the air flow. Not sure if your clutch is mechanicial or electricly driven clutch. If electric check the fuses and wiring, perhaps it wiggled loose. Mechanicial ones will have a resistance when spining them by hand. No resistance then the clutch is wiped out.
I changed the fan clutch, the bearings were worn, not sure if this was the problem, I drove it today (outside temp around 38deg) and the temp ran mid normal. This was with the plow in the raised position. I will see when I load the spreader (8ft with 6in extender sides) if I have any more overheating issues.