CLIB0028

Service Bulletin - Product
S UPPORT
Powering Business Worldwide
Subject: UltraShift® OM Clutch Noise During Rapid Engine Acceleration or
Deceleration
Document Number: CLIB0028
Date: December 13, 2011
Updated: July 7, 2014
Issue Description: During vehicle maintenance/diagnostics of vehicles equipped with
UltraShift OM clutches, maintenance technicians and vehicle operators are noticing a
clunking noise coming from the clutch during no-load engine acceleration from idle or
deceleration to idle. The noise is more noticeable during servicing inside a building or
service bay and when the clutch inspection cover is removed.
The OM clutch is equipped with internal mass weights that provide the force to engage
the clutch. These weights have hard stops at the disengaged (engine idle) and at full
engaged position. While the engine is in a no-load condition , such as transmission in
neutral, the engine accelerates and decelerates at a faster rate than in-gear operation .
This rapid rate causes the mass weights to contact the stops with slightly more force
than in-gear operation, causing the noise. This is normal operation of the UltraShift
DM Clutch.
Certain conditions such as a missing clutch inspection cover may make the noise more
noticeable. As it is a common practice to discard the clutch inspection covers during
service, information from the field suggests installing the OM clutch cover dampens the
noise and makes it less noticeable to the driver, as well as protects the functioning of
the clutch from environmental contaminants.
Containment/Corrective Action :
None, the noise heard during the engagement and disengagement of the clutch during
rapid engine acceleration and deceleration is normal operation . The presence of this
noise after a new service part is installed is not considered a warrantable defect.
Affected Models/Population: UltraShift OM Clutch product
Field Strategy: N/A
Warranty Information: N/A normal operation
The material contained in this bulletin is product improvement information. Eaton is not committed to, or liable for,
FSUD: 2014-FSUD-1732
canvassing existing products.
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