Bulletin No.:

Service Bulletin

19-NA-216

Date:

January, 2020

TECHNICAL
Subject:

Noise, Vibration, and/or Harshness Issues/Clunk Noise Heard During Coast Down
Event

Brand:

Model:

Chevrolet

Silverado
2500/3500

GMC

Sierra
2500/3500

Model Year:

VIN:

from

to

2020

2020

from

to

Engine:

Transmission:

L5P

MGM

Involved Region or Country

North America, Middle East, Israel

Additional Options (RPOs)

NQF (TRANSFER CASE-ELECTRIC SHIFT CONT, TWO SPEED, ALUM)
NQH (TRANSFER CASE-ACTIVE, TWO SPEED, SWITCH ACTIVATED, ALUM)

Condition

Some customers may comment on one or more of the following conditions:
• Noise
• Vibration
• Harshness issues such as a clunk noise heard during coast down event

Cause

Copyright 2020 General Motors LLC. All Rights Reserved.

This condition may be caused by a misalignment between the transmission output shaft
and the transfer case input.

⇒ Transfer case to transmission misalignment could cause the transfer case
shift collar to slip out of engagement.

Page 2

January, 2020

Bulletin No.: 19-NA-216

Correction

5411622

Perform road test:
1. Drive vehicle up to 40 mph (64 km/h) on a smooth, flat road.
2. Allow vehicle to decelerate by coasting in drive to below 10 mph (16 km/h) (do not
use the brakes).
3. Listen and feel for bumps or clunks from the underbody.

⇒ Repeat steps 1-3 at least 8 times.
• If the noise is NOT from the transfer case (2), refer to SI for further diagnostics.
• If the noise has been verified to be from the transfer case, refer to the Service
Procedure below.

Service Procedure
1. Lift the vehicle. Refer to Lifting and Jacking the
Vehicle in SI.
2. If equipped, remove the skid shields. Refer to
Transfer Case Skid Shield Replacement in SI.
3. Remove the three transmission mount nuts.

4. Remove the rubber hose from the transmission
crossmember by removing the bolt and rosebud
clip, as shown.
5. Remove the transmission crossmember by
removing the four bolts attaching it to the frame.
6. Remove the transmission mount from the
transmission. Discard the transmission mount
bolts.
Note: It may be helpful to use a screw jack to raise and
lower the transmission to allow access to all the bolts.
7. Loosen (but do not remove) all 12 transfer case
bolts.

5368737

Bulletin No.: 19-NA-216

January, 2020

Page 3

5368740

Note: It is critical that the gap be a minimum of ½ inch
(13 mm) , but no more than 1 inch (25 mm).
8. Slide the transfer case rearward until there is a gap
of ½ inch to 1 inch (13 mm to 25 mm) between the
transmission and the transfer case.
9. Slide the transfer case forward until it is contacting
the transmission again.

5211401

Page 4

January, 2020

Caution: When you get to bolts 10, 11, and 12 in the
sequence in step 13, it is critical that you remove the
bolts and clean the threads on the bolt and in the
transmission with brake cleaner, then blow out the hole
with compressed air to ensure there is no fluid left in it.
Failure to do this may lead to stripped threads.
10. Tighten the 12 transfer case bolts in the sequence
shown. Torque to 41 ft-lb (55 Nm).
11. Install the transmission mount on the transmission
using two new bolts. Torque to 74 ft-lb (100 Nm).
12. Install the transmission crossmember. Torque the
four transmission crossmember bolts to 85 ft-lb
(115 Nm).
13. Lower the transmission onto the crossmember.
14. Install the three transmission mount nuts and
torque to 33 ft-lb (45 Nm) plus 50 degrees.
15. Reinstall the rubber hose to the transmission
crossmember. Torque the 10mm bolt to 6.5 ft-lb
(9 Nm).

Labor Operation

Bulletin No.: 19-NA-216

16. Clean all residual fluid from transfer case and
transmission.
17. Reinstall the transfer case skid shield. Refer to
Transfer Case Skid Shield Replacement in SI.
18. Lower the vehicle. Refer to Lifting and Jacking the
Vehicle in SI.

Parts Information
Causal
Part

Description

Part
Number

Qty

N/A

Transmission
Mount

11548787

2

Warranty Information
For vehicles repaired under the Powertrain coverage,
use the following labor operation. Reference the
Applicable Warranties section of Investigate Vehicle
History (IVH) for coverage information.

Description

Labor Time

8480898*

Diagnostic Time for Transfer Case Misalignment

0.3 hr

Add

Transfer Case Fasteners Re-Torque and Road Test

2.5 hrs

*This is a unique Labor Operation for Bulletin use only.

Version

3

Modified

Released September 19, 2019
Revised September 30, 2019 - Update Correction section and add Service Procedure
section.
Revised January 08, 2020 - Added engine and transmission RPOs.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.

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