Hello all, my 03 1500 5.3/auto/4x4 has had a clunk in the driveline for the last 40k miles or so. It usually happens when I have slowed to go around a corner and then step back on the gas, or if I am coasting through town and then step back on the gas. It will sometimes do it less severly on the 2-3 upshift also, not all the time. I have checked u-joints, and the ring and pinion for excessive play, and the t-case chain. The only two things I can think of is something inside the tranny or the slip yoke. I do not have the nickel plated one and do not want to pay for it unless I am fairly certain that is my problem. Anyone have any advice on how to determine what my problem is? BTW gm dealer told me it was "normal driveline lash" It literally sounds like a u-joint is so bad it is making 1/2 turn before it bangs,a really metallic clunk sound. I have learned to live with it, but I'd still like to take care of it if I could. Thanks!
Mike

If It Has A Slip Joint Anywhere In The Driveline Grease It...

nope no slip joint

The first of the following bulletins says 2-3/3-2 noise is normal, the second bulletin goes after the 1-2 shift with software and a new PCS on certain models. Hope these help!




Bulletin No.: 01-07-30-042C
Date: September 27, 2005
INFORMATION
Subject:
Information on 2-3 Upshift or 3-2 Downshift Clunk Noise

Models:
2006 and Prior Light Duty Trucks
2003-2006 HUMMER H2
2006 HUMMER H3
2005-2006 Saab 9-7X

with 4L60-E or 4L65-E Automatic Transmission (RPOs M30, M32)
Supercede:
This bulletin is being revised to add additional model years and information pertaining to the 2005 model year vehicles. Please discard Corporate Bulletin Number 01-07-30-042B (Section 07 - Transmission/Transaxle).
Important: For 2005 model year vehicles, refer to Corporate Bulletin 05-07-30-012 or newer.

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 (http://www.alldatapro.com/alldata/PRO~V43850500~C37436~R0~OD~N/0/89012112/94695002/94695101/94695103/34853741/34860071/34860072/56221852) is released and the 3-4 clutch (http://www.alldatapro.com/alldata/PRO~V43850500~C37436~R0~OD~N/0/89012112/94695002/94695101/94695103/34853741/34860071/34860072/56222273) is applied. The timing of this shift can cause a momentary torque reversal of the output shaft (http://www.alldatapro.com/alldata/PRO~V43850500~C37436~R0~OD~N/0/89012112/94695002/94695101/94695103/34853741/34860071/34860072/56225985) 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 (http://www.alldatapro.com/alldata/PRO~V43850500~C37436~R0~OD~N/0/89012112/94695002/94695101/94695103/34853741/34860071/56233126).
This is a normal condition. No repairs should be attempted.



Bulletin No.: 03-07-30-020D
Date: May 05, 2005
TECHNICAL
Subject:
Transmission Has a Harsh 1-2 Shift, Slipping 1-2 Shift Followed by a Harsh Engagement (Replace Pressure Control Solenoid and Reprogram PCM on Certain Models)

Models:
2003 Cadillac Escalade
2003 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2003 GMC Sierra, Yukon, Yukon XL

with 4.8L or 5.3L V8 Engine and 4L60-E Automatic Transmission (RPO M30)
Supercede:
This bulletin is being revised to replace labor code K5364 with labor code J6355. Please discard Corporate Bulletin Number 03-07-30-020D (Section 07 - Transmission/Transaxle).
Condition
Some customers may comment on a harsh 1-2 shift, 1-2 slip shift that has a bump feeling when 2nd gear engages.
Correction
For 2003 model year vehicles produced prior to April 1, 2003, replace the Pressure Control Solenoid (PCS). Refer to the Control and Shift Solenoid (http://www.alldatapro.com/alldata/PRO~V43850500~C37436~R0~OD~N/0/89012112/94695002/94695101/94695103/34853741/34860071/96356795/96356796/56220167) Replacement procedure in the Transmission sub-section of the Service Manual (SI Document ID #825149). Also, reprogram the Powertrain Control Module (PCM).

More than likely, it is your primary driveshaft yoke. I had that same issue, and I thought the rear axle was shifting inside the Ubolts when I accelerated. Not the case. The primary driveshaft yoke needs to be either replaced or greased with a grease that GM recomends. The reason for the noise is because the splines on the output shaft on the tranfer case don't match up correctly with the ones in the yoke. They bind under load and snap. They greased mine and then when it got out of warranty, they replaced it. Problem went away. That was on my 1/2 tonner 5.3 2005

Its your transfer case, my 04 Z-71 did the same DAMN ANNOYING THING!!! Thats one reason i sold it! Lay under your truck and try to rotate your front drive shasft, you will hear the clunk inside the t-case.

try lubing the splines in the yoke going into t case you might be suprised how much noise that can make. I have only used the gm lube so i dont know what to tell you to used just no wheel brg grease needs to be a little thinner.

Thanks guys, I will try to get the gm grease from the stealer, maybe it will dampen it some. Its been my only complaint with the truck...ever. Those new 900's are breaking down my willpower of actually paying a truck off though...lol

Get the grease from the dealer and lube it. Don't waste your money on the Nickel plated slip yoke, it's as worthless as the stock one.

DEWFPO

Get the grease from the dealer and lube it. Don't waste your money on the Nickel plated slip yoke, it's as worthless as the stock one.

DEWFPO
i have put a few of those in trucks under warr and never saw them again. what makes you say that

i have put a few of those in trucks under warr and never saw them again. what makes you say that

I put one in my Ford and it did make the situation better for a while, but eventually, the clunking came back and the only way to keep it in check is with routine lubes, even the nickel units.

Just my experience. Maybe the GM units use a better grade of nickel.

DEWFPO

i dont think gm makes anything "better" a lot of times when they get out of warr I dont see them anymore period.

My 01 clunked quite a bit to. If you got under the truck it had a ton of lash in the rearend and transfer case.

Yeah I think it is just a general lash throughout the whole driveline. I think I am going to order a nbs 07, hopefully it wont develop the same problem.

lightly grease the yoke

Already did.... no difference...

just on the outside,

when you jump in the bed or bounce on the bumper do you hear it? if so check your shocks, but it is most likey the lash in the drive line.