Low pitched whining noise in 1st gear

[Ben S]

Yesterday on the way home from work in stop and go traffic with the ambient temperature in the high 90s I noticed an intermittent low pitched whining noise as the truck accelerated from a stop. These were normal accelerations..not racing anyone. The best way I know to describe the noise is that it sounded like a radiater clutch fan but louder and vibrated the truck just slightly. No change in driveability or fluctuation in power.

Went for a drive today...ambient temps in high 80s and did not hear this noise. Nothing is leaking from the truck.

Engine and truck are stock.

Truck is going for HVAC service Monday anyway...any thoughts?



Ben