GHG17 DD Medium Duty Operators Manual 2. Heat from normal engine operation may, over a period of time, cause the fluid within the damper to break down and lose its dampening properties. For this reason, replace the viscous vibration damper at time of normal major engine overhaul, regardless of apparent condition. All information subject to change without notice. 81 DDC-SVC-MAN-0192 Copyright © 2017 DETROIT DIESEL CORPORATION