THERE IS ONLY 2-3 LBS. OF BOOST ON MY SUPERCHARGER.
THE TRUCK SAT FOR A FEW MONTHS.
I HAD OIL CHANGED TO SPEC OIL( I HOPE)
NOTICABLE WHINING WHEN I DROVE IT INITIALLY.
PUT 'BELT DRESSING' NO CHANGE.
TOOK TO 5.0 SHOP --SAID BYPASS VALVE MAY BE CAUSE.
THAT WAS A LOT LESS THAN DEALER'S 'TOTAL BLOWER REPLACEMENT'... BUT STILL, ANY IDEAS?
TRUCK IS 46 K MILES OLD

 

Have you tried unplugging the bypass solenoid and testing it out?
If its defective I am not sure if unplugging it would change things or not?

 

at least make sure it is closing the vavle all the way.
It is vacuum operated.

Located on the drivers side of your blower, near the back of it (on that corner)

Check the bottom of the solenoid, It has a little "arm" that moves up and down and opens and closes the boost dump valve on the supercharger.

It is a BEETCH to get at, there are 2 bolts holding it on.

I'd start there

 

Heres what you should do. Crank truck.Look at the bypass valve. It should be all the way at the top where you cant see it. Now unplug the vacume line thats on the top of the valve. The arm on the bypass should drop down onto the stopper(closed). IF it drops down then im not shure what the problem is but it has to be vacume related. IF it doesnt drop down then its time to start pulling it apart and checking to see if the acuater is even working. And after that the S/c might need to be pulled to check out the rotors and see if they are in one piece. Hope my long post about nothing helps somehow.

 

I don't think 5.0 pro shop in amherst knows exactly what they'redoing.

I'm sure they can throw a few mods on, but they're not Lightning specialists.