Service Campaign S4644

January 2026

Front Engine Accessory Drive Update
Release: 1

Technician Skill Level: A

Revision Note: 11/2025 Initial Release

Market: North America

Service Category: Service Department

Applicability: Please refer to VDA+

Section: Function Group 263
Description:
Vehicles were assembled using the incorrect front engine accessory drive (FEAD) components.
Concern:
Incorrect FEAD components can lead to premature failure of the accessory belts.
Action:
Use the instructions in this document to install the correct FEAD components.
Warranty Information
This repair is covered by an authorized Service Program. Reimbursement is obtained through the
normal claim handling process.
Claim Type (used only when uploading from the Dealer Bus. Sys.)
B
Labor Code

Description
Drive Belt, Belt Tensioner, and Idler Pulley,
Replacement (All)

Hours

3218-03-02-01

Alternator Mounting Bracket, Replacement

0.7

3218-03-02-05

Belt Tensioner, Alternator, Replacement

0.5

Main Code

2634-03-03-10

Causal Part

24390274

SCC Authorization Code

S4644

Expiration Date

January 31, 2027

0.7

Service Campaign S4644

January 2026

Front Engine Accessory Drive Update
Parts Information
Order using the normal process
Part Numbers

Part Names

Quantity

24170327

Idler Bracket (Fan Belt)

1

24390274

Idler Pully (Fan Belt)

1

24389899

Tensioner (Fan Belt)

1

24338502

Belt (Fan)

1

60112984

Socket Screw, Tensioner (Fan Belt)

1

24147478

Alternator Bracket

1

24377136

Tensioner (Alternator Belt)

1

984759

Tensioner Flang Screw (Alternator)

1

23857789

Alternator Belt

1

Repair Procedure
1. Park the vehicle on level surface.
2. Apply parking brake.
3. Place the transmission in park or neutral.
4. Turn off ignition.
5. Install wheel chocks.

Service Campaign S4644

January 2026

Front Engine Accessory Drive Update
6. Disconnect the cable from the negative terminal.

7. Disengage the fan belt tensioner.
8. Remove and discard fan belt.

Service Campaign S4644

January 2026

Front Engine Accessory Drive Update
9. Close the shut-off on the coolant filter housing and remove filter (Only required if equipped
with a coolant filter). (Retain filter for reinstallation)

10. Remove and discard the idler pulley and tensioner assembly. (Retain mounting hardware for
reinstallation)

Service Campaign S4644

January 2026

Front Engine Accessory Drive Update
11. Disengage the alternator belt tensioner.

12. Remove and discard alternator belt.

Service Campaign S4644

January 2026

Front Engine Accessory Drive Update
13. Remove and discard the alternator belt tensioner and mounting hardware.

14. Disconnect alternator electrical connections.
15. Remove alternator. (Retain alternator and hardware for reinstallation)

16. Remove and discard alternator mounting bracket. (Retain mounting hardware for
reinstallation)

Service Campaign S4644

January 2026

Front Engine Accessory Drive Update
17. Install and torque new alternator mounting bracket (PN-24147478). (Use retained hardware)
Tightening torque
60 ±10 Nm (44 ±7 lbf⋅ft)

Alternator Mounting Bracket, screws
18. Install and torque alternator.
Tightening torque
Alternator, screw

60 ±10 Nm (44 ±7 lbf⋅ft)

18. Connect alternator electrical connections.
Tightening torque
Alternator Terminal Nut

12 ±2 Nm (9 ±1 lbf⋅ft)

Service Campaign S4644

January 2026

Front Engine Accessory Drive Update
21. Install and torque new alternator belt tensioner (PN-24377136) and mounting bolt (PN-984759).
Tightening torque
Belt tensioner, screw

19. Disengage alternator belt tensioner.

48 ±8 Nm (35 ±6 lbf⋅ft)

Service Campaign S4644

January 2026

Front Engine Accessory Drive Update
20. Install the new alternator belt (PN-23857789).

21. Install and torque the new fan belt idler pulley bracket (PN-24170327).(Use retained hardware)
Tightening torque
Idler Pulley Bracket, screws

60 ±10 Nm (44 ±7 lbf⋅ft)

Service Campaign S4644

January 2026

Front Engine Accessory Drive Update
22. Install and torque the new idler pulley (PN-24390274).
Tightening torque
Idler Pulley, screw

50 ±5 Nm (37 ±4 lbf⋅ft)

23. Install and torque new fan belt tensioner (PN-24389899) and mounting hardware (PN60112984).
Tightening torque
Idler Pulley Bracket, screws

60 ±10 Nm (44 ±7 lbf⋅ft)

Service Campaign S4644

January 2026

Front Engine Accessory Drive Update
24. Disengage fan belt tensioner.
25. Install new fan belt (PN-24338502).

26. Install retained coolant filter and open the shut-off on the coolant filter housing. (Only required
if equipped with a coolant filter).

Service Campaign S4644

January 2026

Front Engine Accessory Drive Update
27. Connect the cable from the negative terminal.

28. Remove wheel chocks.

29. Release truck.