[lurch115]

okay, here is the closest thing i could come up with since Haynes Manuals don't have crap for automatic transmissions in them.....that solenoid is part of the TCS system(transmission controlled spark).... basically what that solenoid does send a signal to another electronic solenoid when the transmission is operating in low forward gears. Which in turn allows the other solenoid to vent all vacuum pressure that would normally go to the vacuum advance out into the engine compartment.......so basically that solenoid is what helps to eliminate the vacuum advance from operating in normal in town driving....(35mph or under) make sence??? keep in mind...this was the only thing i could find that it could be.... i might stop by the Chevy dealer tomarrow on my way home and see if they can tell me what it is for sure....but i think what i put above is what it is for....



sorry for the long post...