Here’s the background:
Two weeks ago I drove out to a Chicago-area tuner to have a Stage IV tranny put in. I also had them install their own long-tube headers, a Yank SY3500 and then do dyno-tuning. Everything was fine during the ride home to Washington, DC and for a few days afterwards.

Then here’s what developed during the last week…
I started get a cresandoing-noise that seems to occur when I accelerate. This noise happens under normal city driving, not just WOT. This graduating-noise seems to occur when I load the gears in the transmission on one side but also happens in a diminishing fashion when I decelerate, which loads the gears on the other side. It almost sounds like a turbine winding up when I accelerate and then vice-versa when I decelerate. It is hard to tell if there is a ‘grinding” sound to this but it has gotten worse to the point of being able to hear this noise over the sound of my headers, off-road pipes and B&B PRTs (which are very loud).

I have noticed the sound in both Overdrive and Third gears. When I take my foot off the gas while accelerating, the noise immediately stops until the car starts to decelerate. This leads me to believe the noise is directly related to something wrong in the drivetrain. It is getting worse and worse (louder).

Any ideas what this horribly-irritating noise can be? Thanks in advance!

 

Sounds like something is very wrong with the tranny...

vetterdstr :cheers:

 

:iagree: Don't do further damage...get it back to the tuner to diagnose.! :cheers:

 

Any idea if these GUT-WRENCHING sounds could be caused by not using the GM quieting-additive in the differential? ...Or am I just grasping at straws?

Technical help, please...my mechanic is on vacation as is the person who built & installed the Stage IV tranny.

What about the following possibilities:
- a bad differential (installed a Z06 3.42 less than a year ago)
- the Yank torque converter "balooning"
- a bad front pump in the transmission