There is already a report on the 2-3 shifts i just found, according to them it's normal.

A/T - 2-3 Upshift or 3-2 Downshift Clunk Explanation

File In Section: 07 - Transmission/Transaxle

Bulletin No.: 01-07-30-042A

Date: December, 2002

INFORMATION

Subject:
Information on 2-3 Upshift or 3-2 Downshift Clunk Noise

Models:
2003 and Prior Light Duty Trucks
with 4L60E or 4L65E Automatic Transmission (RPOs M30, M32)

This bulletin is being revised to add the 2003 model year as well as information about 3-2 downshift Please discard Corporate Bulletin Number 01-07-30-042 (Section 07 - Transmission/Transaxle).

Some vehicles may exhibit a clunk noise that can be heard on a 2-3 upshift or a 3-2 downshift.

During a 2-3 upshift, the 2-4 band is released and the 3-4 clutch is applied. The timing of this shift can cause a momentary torque reversal of the output shaft that results in a clunk noise. This same torque reversal can also occur on a 3-2 downshift when the 3-4 clutch is released and the 2-4 band applied. This condition may be worse on a 4-wheel drive vehicle due to the additional tolerances in the transfer case.

This is a normal condition. No repairs should be attempted.

 

That bulletin is a bunch of Hokey. My 99 does the same thing, and I eat GM sealed U-Joints like Candy. When under warranty I had it in there 3 times, and then I got fed up and put in a Greasable joint myself.

They also tried addressing the Yoke Clunk with Lithium grease, still does it.
Too bad they didnt drill in a Zert fitting on the side of it, like the BIG trucks have... that way, every oil change, you can squirt a little bit in.
C

 

mine is mainly the 1-2, corners reverse and downshifting. does this cause any damage in the long run? how can i greese it?