Tranny shift knock?

[atrautweiler]

I have a 2003 sliverado z71 w/ 25k. When the tranny shifts from 1st to 2nd, and especially 2nd to 3rd, there is a banging sound. The problem is intermittent but happens mostly when accelerating slowly. Has anyone had this problem?

[seadoons]

Yes, I have this exact problem and it is annoying as hell. Mine shutters from 1 to 2, and the entire truck shakes bad. The fix for this is to replace some sort of solenoid (sp) in the transmission. The problem is that this part is on national backorder, and has been for a long time. I have put almost 12,000 miles on my truck since that part was ordered for me, but I have kept in touch with the dealer and it is supposed to be in at the end of this month. For the 2-3 shift, I sometimes hear a clunk, but there was a TSB put out for this and it was described as normal with no fix available. I still throw the bulls**t on that one. No vehicle should make a clunk noise when shifting. I figured they had fixed that problem for the 2003 models though. Oh well, its very frustrating.

[Rammer]

Here's the TSB for that.

 

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.