No.: 18 TS-4Rev
November 29, 2018
TO:

Service Locations

FROM:

Service Systems Development

SUBJECT:

DD Heavy Duty Platform Accessory Drive Belt

Note: This document supersedes 11 TS-11, 12 TS-10, 13 TS-29, 14 TS-28, and 17 TS-9.

ISSUE
The belt drive system is creating noises and/or throwing belts. It’s possible to misdiagnose a
belt tensioner as the primary failed part.
Material testing and inspections in Detroit shows a high No Trouble Found rate on belt
tensioners. This is due to some repair shops not following the symptom-based troubleshooting
“Belt Coming Off” or “Belt Drive Noise” found in the troubleshooting manuals.

CAUSE
Winter is prime-time for old, worn out, and aged belts to begin squeaking (noise) due to material
hardening and excess moisture. Belts are a maintenance item and are not covered under any
warranty.
The belt drive system on the front of the engine is a complex system consisting of numerous
components that must work in harmony with each other in order to function correctly. Normal
variation in the alignment of these parts and worn out belts can lead to noisy belts and throwing
of belts.

REQUIRED ACTION
In September, 2016, and October, 2017, symptom-based troubleshooting “Belt Drive Noise”
(found in the “Noise” chapter) and “Belt Coming Off” were updated in the EPA07/10/GHG14
DDEC VI/10 Electronics and Troubleshooting Manual (DDC-SVC-MAN-0084) and GHG17
Troubleshooting Manual (DDC-SVC-MAN-0191). This troubleshooting must be utilized. Do not
replace the belt tensioner unless the troubleshooting calls for it. For these complaints, a new
belt or belts will usually correct the problem. A belt coming off after installation is typically due to
improper installation of the belt, or the use of an incorrect belt. Continued noise after belt
replacement is typically due to improper installation of the belt, damaged belt pulleys, pulley
contamination from old belt material or fluids (coolant, oil, fuel, belt dressing, etc.), or use of an
incorrect belt. When replacing the belts, reference the “Poly-V-Belts” chapter in the
EPA07/10/GHG14 Engine Manual (DDC-SVC-MAN-0081) and the “Belt Drive” chapter in the
GHG17 DD Platform Workshop Manual (DDC-SVC-MAN-0190). These chapters were updated
in February, 2018. Various belt information videos were published in February, 2018, and can
Detroit Diesel 13400 Outer Drive, West / Detroit, Michigan 48239-4001

18 TS-4Rev

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12/4/2018

be found on DTNAConnect.com > Reference > Detroit Multimedia > DD Platform > Belt
Tensioner.
In October, 2016, the belt maintenance interval was reduced to 150,000 miles for long haul
service and 105,000 miles for short haul and severe service. Reference the DD Platform
Operators Manual (DDC-SVC-MAN-0189) found on DTNAConnect.com > Search Literature >
Detroit Literature > DD13/DD15/DD16. No logon is required to access this manual.
In March, 2018, new belts became effective at the truck plants to reduce belt issues by better
accommodating variability in the belt drive system. These belts carryover the improvements first
advertised in Technical Service letter 17 TS-9 for service-only belts for the DD13/DD15 onhighway truck engine with the variable speed water pump. These belts are now released for
production with a new part number, and are joined by new belts for the fixed speed water pump
for all EPA10 and later on-highway truck engines.
Do not use belts from incorrect engine types. For instance, don’t use a belt from an engine with
a fixed speed water pump on an engine with a variable speed water pump. The fixed speed
water pump belt is 9mm longer and results in slack in the belt with the tensioner operating near
the end stops and can cause the belt to come off. Refer to PartsPro on DTNAConnect.com for
the latest belt part number information for a particular unit.
REQUIRED MATERIAL
If the belts do need replacing, Table 1 provides a list of the new belt part numbers that
superseded the prior part numbers. Stock of the former part numbers CANNOT be returned.
Application

Engine Model

DD13 on-highway
truck

EPA10 DD13: 471903, 471911, 471913
GHG14 DD13: 471927
GHG17 DD13: 471928

DD15/DD16 onhighway truck

EPA10 DD15: 472903, 472904
GHG14 DD15AT: 472906
GHG14 DD15TC: 472909
GHG14 DD16: 473908
GHG17 DD15: 472910
GHG17 DD16: 473910

Table 1 – Service Belt Part Numbers

Water
Pump

Former P/N’s

New P/N

Variable
Speed

DTNA: 01-32732-671
Detroit: A4719932796

A4719935696
or
A4719935496

Fixed
Speed

DTNA: 01-32732-680
Detroit: A4719931896

A4719935596

Variable
Speed

DTNA: 01-32732-691
Detroit: A4729932296

A4729933496
or
A4729933296

Fixed
Speed

DTNA: 01-32732-700
Detroit: A4729931896

A4729933396

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See Figure 1 below for help in identifying units with the variable speed water pump.

Variable Speed Water Pump

Fixed Speed Water Pump

Figure 1 – Water Pump Identification

CLAIM PROCESS
Normal in-warranty procedures apply. Proactive removal of properly functioning parts is not
allowed under warranty. Again, belts are maintenance items and are not covered under any
warranty.
CONTACT INFORMATION
Please contact the Detroit™ Customer Support Center at 800-445-1980 or email
[email protected] if you have any questions.