Traded my 03 on 06 last week with 36K.. I love the truck, but no cherp when I shut her down,,,Did they change something to get rid of it?

 

Yea there was a tsb for the older ones that changed the pully on the alternator to stop that from happening. So all of the new ones should have the updated pully.

 

they probably change from the old style goodyear belt to a gatorback belt. Mine used to chirp too but when i changed belts it stopped. Doubt it was just the pulley change that stopped it.

 

Pulley has a one way clutch in it. As engine dies and compression pushes backwards the clutch slips on alternator.

 

Yup, it's called an overrunning clutch pulley, and TSB 09-004-06 specifically addressed the belt chirp. The pulley is part number 05183490AA, and as stated above, replaced the drive pulley on the alternator. Due to the rotor's iron and copper wire mass inside the alternator, the alternator shaft continues to turn when the crank suddenly stops the belt because of the engine's high compression, which causes the chirp. The overrunning pulley allows slippage one way, but not the other- the belt can turn the alternator, but the alternator can't turn the belt. I remember my father's first generation truck chirp every time he shut it off. Mine did it too, sometimes more than others, until I had the TSB done by choice. I imagine that with a heavy electrical load (field winding highly energized) at shut down, the chirp is less pronounced as the field adds drag on the rotor.

 

mine use to chirp, witht he stock belt, but i went to gator back belt, and its gone, i don't miss the chirp, but i know i can put the stock type belt back on if i ever wanted it back.