ok ive got an 09 express work truck. 6.0L 4L85E trans. when accelerating it has a crazy wind noise coming from the transmission. ive pulled it apart and dont see anything wrong with the clutch packs. valve body looks solid. all shift solenoids look fine and passed the test. im just stumped. no metal shavings. no burnt fluid. shifts and drives fine. but the whine kills me.

Work your way to the wheels, (diff/axles)

You sure it’s not a ujoint or a bearing?

new u juint and carrier assembly. its not the pinion of the rear. its most certainly coming from the transmission.

its been driving me nuts. its almost like radio interference whining but its mechanical. hard to explain

go spray down your belt with wd40 and see if the sound goes away

well i dont know if the wd helped. however it did make me take a closer look at my harmonic balancer which in fact, was splitting at the rubber.



i chased this problem for a year. tore it apart myself and had 2 different shops look into it. and it was a harmonic balancer.

That's a nut punch, been there man