SAFETY RECALL
Mack Trucks Inc.
Greensboro, NC USA

Note: Also applies to Mack Trucks Australia.

Date

Number

Page

5.16

SC0403

1(12)

Interaxle Yoke Retaining Nut
SAFETY RECALL INFORMATION
Mack Trucks Inc. has determined the cap nut that retains the interaxle driveshaft yoke to
the rear axle input shaft may be subject to premature loosening on certain CHU, CMH,
CMM, CXU, GU, LEU, LR, MRU and TD model vehicles. The potential risk is that if the
nut comes off, the yoke can separate from the axle input shaft and cause the driveshaft
to disconnect. If this occurs, a disconnected driveshaft can disable the vehicle and result
in debris in the roadway, which increases the risk of a vehicle crash.
To address these concerns, Mack has developed an inspection and repair procedure
that will help identify suspect components and prevent the possibility of future damage.
Follow the procedure outlined in this document.

VEHICLES AFFECTED
Certain 2012 through 2015 model Mack vehicles manufactured from September 1, 2011
through April 30, 2014 equipped with Mack proprietary axle. Models and Model Years
are CHU, CMH, CMM, CXU, GU, LEU, MRU, TD 2012 – 2015; LR 2015.

VEHICLE QUANTITY
There are 25,588 (20,741 U.S., 1068 Canada, 405 Mexico, 415 Australia, 2959 Export)
vehicles affected by this recall.

REQUIRED PARTS
•
•

21187820 – Yoke Cap Nut
U-Joint Strap/Bolt Kit (see table on page 2)

OPTIONAL PARTS (replace only if needed, see Step 10)
•

21126859 – Pinion Seal

REQUIRED TOOLS
•
•
•
•
•
•

88800551 – Special Clamp Plate
88800552 – Bearing Cone Installation Tool
88800553 – Bearing Seal Installation Tool
88800554 – Yoke Installation Tool
2.5-inch ¾-16UN Hex Head Bolt
¾-Inch Flat Washer

Page 2

To schedule parts orders, please call 1-877-986-5862 and provide the following:
•
•
•
•

17 digit Vehicle Identification Number (VIN)
Recall Number (SC0403)
Dealer Code
Purchase Order Information (PO Information)

U-JOINT KITS
Note: Refer to the manufacturer for the correct U-joint hardware kit
Driveline Series
MXL 18XT
1810 HR
SPL250HD HR
MXL 176XT
1760 HR
SPL250HR
MXL 17XT
1710 HR
SPL170 HR
MXL 17XN
1710 FR
MXL 17T

Hardware/Kit
8235-KT17SB
2104-657018X
2104-212214X
8235-KT17SB
2104-657018X
2104-2507018X
8235-KT17SB
2104-657018X
2104-1707018X
8235-S165B2
2104-673209
8235-KT17SB

Quantity
1
1
1
1
1
1
1
1
1
4
4
1

Mack Trucks, Inc.
Safety Recall

Date

Number

Page

5.16

SC0403

3(12)

REPAIR PROCEDURE
You must read and understand the precautions and guidelines in Service Information,
Function Group 40, “General Safety Practices” before performing this procedure. If you
are not properly trained and certified in this procedure, ask your supervisor for training
before you perform it.
Note: Information is subject to change without notice. Illustrations are used for reference
only, and may differ slightly from the actual vehicle being serviced. However, key
components addressed in this information are represented as accurately as possible.

Do not attempt to repair or service this vehicle without having sufficient
training, the correct service literature and the proper tools. Failure to
follow this could make the vehicle unsafe and lead to serious personal
injury or death.

1. Verify service program eligibility by checking service program status in VDA.
2. Secure the vehicle for service by parking it on a flat level surface, applying the parking
brake, chocking the rear wheels, and placing the transmission in neutral.
3. Raise the rear axle, place jack stands underneath the axle.
4. Release the parking brake.
5. Remove fasteners on rear axle U-joint. Discard fasteners.

Page 4
6. Remove U-joint and shaft from rear axle yoke.

7. Secure driveshaft to frame.

Mack Trucks, Inc.
Safety Recall

Date

Number

Page

5.16

SC0403

5(12)

8. Remove bevel pinion nut. Refer to UCHP instructions for disposition of the nut.

9. Use a hand-held wire brush to clean locking compound from the bevel pinion threads.
10. Inspect the pinion seal for leakage.
- If no leakage exists, apply the park brake and proceed to Step 20.
- If leakage exists, proceed to Step 11.

Page 6
11. Install special tool 88800551, with a 2.5 inch ¾-16UN hex head bolt, on bevel pinion
shaft.

Mack Trucks, Inc.
Safety Recall
12. Remove yoke using suitable puller.

Date

5.16

Number

Page

SC0403

7(12)

Page 8
13. Remove pinion seal and discard.

14. Remove debris and excess oil from seal housing bore.

Mack Trucks, Inc.
Safety Recall

Date

5.16

Number

Page

SC0403

9(12)

15. Insure the seal installation tool is clean and free of nicks or damage that would cause
premature seal failure. Apply lubricant to the seal lip and position the seal on tool
88800552. Apply a light film of lubricant on the outside diameter of the new seal and in
the seal housing bore. Lubricate the bolt threads and under the bolt head. Install a flat
washer on the bolt and thread the bolt through the seal tool and into tool 88800551.

16. Turn the bolt to fully seat the seal in the housing.

17. Slide yoke onto shaft over top of 88800551.

Page 10

18. Apply the park brake.
19. Install 88800553 on top of yoke. Lubricate the bolt threads and underneath the bolt
head. Install a flat washer on the bolt and thread the bolt through the seal tool and into
tool 88800551. Hand tighten bolt until yoke bottoms out. Remove tools from bevel pinion
shaft.

20. Verify cleanliness of the bevel pinion threads. If necessary, use a hand held wire brush
to clean locking compound from the bevel pinion threads.
21. Install new bevel pinion nut. Thread nut by hand for the first few threads, then use an air
tool to tighten nut until it stops.

Mack Trucks, Inc.
Safety Recall

Date

Number

Page

5.16

SC0403

11(12)

22. Using a torque multiplier and a torque wrench, torque tighten bevel pinion nut to 1220 +/136 Nm (900 +/- 100 lb-ft).

23. Release the park brake.
24. Remove the strap from the driveshaft securing shaft to frame. Install driveshaft in
position on yoke, hand start new fasteners.

25. Refer to the manufacturer for the correct U-joint torque values.
26. Raise rear axle and remove jack stands. Lower rear axle.
27. Apply parking brakes.
28. Remove wheel chocks.
29. Check gear oil level and add oil as necessary before returning vehicle to service.

Page 12

REIMBURSEMENT
This repair is covered by an authorized Safety Recall campaign. Reimbursement is
obtained through the normal claim handling process.

Claim Type

(used only when uploading from the Dealer Business System)

40

Recall Status
Vehicle repaired per instructions
Labor Code
Primary Labor Code, Yoke Cap Nut Replacement

4651-03-02-12 – 0.6
hrs

Additional Labor Code, Yoke Seal Replacement

4651-03-09-01 – 0.2
hrs

Time to take charge of vehicle and determine
campaign status

1700-16-01-01 - 0.3 hrs

Parts Disposition

Claim material must be
held for seven days
following the claim
going on a credit
statement.

Causal Part

21187820

SCC Code

C6577

Note: Take Charge Time is not included in the labor code for this operation. Take
charge may be eligible, but can only be used once per vehicle repair visit. If the vehicle
is having other warranty repairs performed, take-charge should be charged to the
warranty repair, otherwise take-charge can be charged to this Safety Recall campaign.
Note: Dealers are to perform Safety Recall Campaigns on all subject vehicles at no
charge to the vehicle owner regardless of mileage, age of vehicle or ownership (original
purchaser or subsequent purchasers). Whenever vehicles are subject to a safety recall
are brought to your dealership for service, or taken into your dealership vehicle
inventory, it is strongly recommended that every effort be made to perform the recall
correction before the vehicle is sold or released to the owner.