4/4 drop

[Jonmalibuss]

Just to let you guys know I have the carrier bearing relocater from mc gaughys installed and it helped but did not eliminate the vibration. I installed 4* shims last weekend before I left for vacation, I installed them so they rotated the pinion down to put more angle in the u-joint. I just used some basic knowledge, I was only getting a vibration on hard acceleration which told me that I was probably seeing 0* of angle when the pinion rotated up on take off. So now all vibration is gone! Just need some caltracs now!

[tawss04]

I don't know if they started putting the drive shafts with the double ujionts on the newer thucks, GM had a problem with a luanch shudder on the 2wd etd cab truck when they went to this body. I don't remember seeing any on the newer trucks. My freind who is the service manager at dealer I worked at has a 00 2wd etd cab truck and lowered it 2in in the rear and had the same luanch shudder, he swapped the drive shaft and eliminated it.

File In Section: 04 - Driveline Axle

 

Bulletin No.: 02-04-17-001A

 

Date: July, 2002

 

TECHNICAL

 

Subject:

Launch Shudder/Vibration on Acceleration

(Replace Propeller Shaft and Install New Pinion Flange/Seal)

 

Models:

1999-2003 Chevrolet Silverado 2WD 1500 Series

Extended Cab Short Box Pickups

1999-2003 GMC Sierra 2WD 1500 Series Extended Cab Short Box Pickups

With 4L60-E Automatic Transmission (RPO M30)

Except QUADRASTEER (RPO NYS) Equipped Vehicles

 

This bulletin is being revised to add Model information. Please discard Corporate Bulletin Number 02-04-17-001 (Section 04 - Driveline Axle).

 

Important: Implementation of this Service Bulletin by "GM of Canada" dealers requires prior District Service Manager approval.

 

Condition

 

Some customers may comment on a vibration when accelerating from a stop. This is also known as launch shudder. This condition may occur between 0-40 km/h (0-25 mph) and be more noticeable when the vehicle is carrying cargo or used for towing.

 

Correction

 

A new propeller shaft, P/N 15071486, has been developed to correct this condition. The new propeller shaft incorporates dual double cardan joints on the center and rear joint positions. Refer to Corporate Bulletin Number 02-00-90-002 for lubrication information.

 

The new propeller shaft will require the installation of a new pinion flange kit, P/N 15071485. The pinion flange kit consists of the following components:

 

^ A pinion flange

 

^ Hex bolts (four)

 

^ A pinion seal

 

^ A rear axle drive pinion nut

 

 

Replace the propeller shaft with the new propeller shaft using the following procedure. Use the part numbers listed below.

 

1. Remove the propeller shaft assembly and the center bearing. Refer to the applicable Propeller Shaft Replacement procedure in the Propeller Shaft sub-section of the Service Information (SI).

 

Important: In step 2, you must measure the pinion and differential preload. This information is needed to set the preload of the new pinion flange to the correct specification and to reduce any rear axle noise concerns.

 

2. Remove the drive pinion yoke and the pinion oil seal. Refer to the Drive Pinion Flange/Yoke and/or Oil Seal Replacement procedure in the Rear Drive Axle sub-section of the Service Information (SI).

 

Important: In step 3, use this procedure as a guideline to install the pinion flange to the drive pinion and to set up the proper pinion bearing preload.

 

3. Install the new pinion oil seal, the new pinion flange and the new drive pinion nut. Refer to the Drive Pinion Flange/Yoke and/or Oil Seal Replacement procedure in the Rear Drive Axle sub-section of the Service Information (SI).

 

4. Install the new propeller shaft assembly and the new center bearing. Refer to the applicable Propeller Shaft Replacement procedure in the Propeller Shaft sub-section of the Service Information (SI).

 

Tighten

 

^ Tighten the propeller shaft flange bolts to 70 N.m (52 lb ft).

 

^ Tighten the center bearing support nuts to 40 N.m (30 lb ft).

 

 

5. After completing the repair, operate the vehicle in order to verify that the condition has been corrected.

 

 

 

 

 

 

 

 

Parts Information

 

Parts are currently available from GMSPO.

 

Warranty Information

 

 

 

 

 

 

 

For vehicles repaired under warranty, use the table shown.

 

 

 

 

 

 

 

DISCLAIMER

 

 

 

 

 

 

 

 

 

 

© 2005 ALLDATA LLC. All rights reserved.

Terms of Use

Hope this helps

[ledfoot]

Jon,

 

I also have a vibration, between 10-25mph under acceleration. More strange is a slight (and I mean slight) vibration under braking from 70 mph or so. ??

 

So the McGaughy's kit and the shims eliminated the vibration completely?

 

-Jeff

[Jonmalibuss]

Jon,

 

I also have a vibration, between 10-25mph under acceleration.  More strange is a slight (and I mean slight) vibration under braking from 70 mph or so.  ??

 

So the McGaughy's kit and the shims eliminated the vibration completely?

 

-Jeff

<{POST_SNAPBACK}>

I still seem to have a slight and I mean very slight vibration (almost not even noticable) just on a hard launch. I think with a set of caltracs the problem would be gone because it would eliminate the axel wrap causing the pinion to be thrown out of whack. I havn't noticed a vibration durring braking that would be comming from the driveline, but I do get like a slight growling I guess you could call it everyonce in a while I just figure it's from the brakes being hot or the rear drums. I only feel this in the pedal leading me to belive it is the brakes them selves not the driveline. I have also heard someone else with a VHO complaining about the same problem so I figure it's just another one of GM's "built in failures" the truck still stops just fine.

[Jonmalibuss]

I would like to see some pics of these replacement parts if you plan on taking this route. I would figure by now they would have just decided to install it at the factory.

[ledfoot]

Jon,

 

Do you have the measurement that the carrier bearing relocator changes the location of the driveshaft?

 

Thanks

Jeff

[Jonmalibuss]

Jon,

 

Do you have the measurement that the carrier bearing relocator changes the location of the driveshaft?

 

Thanks

Jeff

<{POST_SNAPBACK}>

I couldn't tell you exactly off the top of my head but if you get under there with a measuring tape and measure from the bracket that the carrier bearing is bolted to, to the center line where the drive line comes through and then double that # because the relocator just flips the carrier bearing to the top of the stock bracket. There is also cutting required to the stock bracket for the relocator and it's not reversible unless a plate is made and welded in place.

 

EDIT: The relocator is adjustable but not very much you can't even adjust it as much as the holes are slotted. I laughed when McGaughys told me that I would not need it with a 4/4 drop.