Noise At 2-3 Shift?

[skip10ga]

Ok here's my truck info:

 

2009 GMC Sierra 2wd, reg cab, long box, 5.3L, 6spd auto. 24,000 km.

 

It happens when trucks's dead cold, or warmed up, even after truck being driven for a 2hr trip.

 

When the trans shifts from 2-3, i head this short "uurt" like a little "mid pitched grunt" almost a small quick vibration. It is louder and more easily heard when pulling away slowly, and the 2-3 shift is about 1500rpm. the shift feels normal, not too soft, and not too hard, but it makes this friggin' noise only at the 2-3 shift!

 

Truck just started doing this, last week, never did it before, and I've owned this truck since it was new.

 

The noise is less audible if I'm harder on the throttle, but I can still hear it when the 2-3 shift happens.

 

This noise is not present at any of the other shifts, and every shift feels normal. No flair, or slip etc on any shift, even when the noise happens, the shift feels normal.

 

Please HELP!!!!! I've searched the web far and wide, but can't seem to find any info on it. You guys are my last chance. I love this truck, and I plan on keepin' her for long, long time, so I just gotta get it figured out.

 

Thanks, in advance fellas. I'm glad to have found this forum, looks like a great bunch of guys on here.

 

Steve-0.

[txab]

Warranty.

[gmtech4]

warranty is right ,

 

 

not your concern bud

 

5 yr powertrain