Vibration Noise

[SilveradoWV]

I remember that post about the vibration noise from the tranny, like between shifts. Most people said they had theirs reprogramed but lost MPG. Just wondering what the noise actually is and if it can do damage!

[GreenRado]

WV,

 

How's southern WV?  I had this issue, if you're referring to the "growl" when the trany shifts into lockup then OD @ around 40 mph.  They flashed a new PCM code that doesn't allow the OD shift till around 53 mph (when you're not "on it").  It worked, and honestly, I don't see where guys were losing mileage - mine has been EPA all the time 15/18.  Last summer I drove thru Okla, TX and NM 80mph+ loaded for camping, w/ topper and air on about 1/2 time, and got 18.9!!!

 

I can see a little drop, bu no way this caused 3-4 mph as a few were saying!

[SilveradoWV]

Southern WV is Hot and Humid as always. Thats the noise I was referring to, might have to check into that. Just wondering if its doing any damage the more I put it off??? Well thanks for the help!

[GreenRado]

In Beckley, the nights always cooled off though, no matter how hot and humid it got during the day.

 

I never got the impression that it did any damage, just an annoyance mostly.  I'm guessing that it's some sort of low-RPM harmonic among drivetrain components.  ???  ???