A/T 6L45R - Normal Clicking/Whistling Noises
SI B24 04 11Automatic Transmission
July 2011
Technical Service
SUBJECT
6L45R - Clicking or Whistling Noises Are Evident at Times
MODEL
All with 6L45R (GM6) Automatic Transmission
SITUATION
1. The customer may complain of a frequent whistling and/or buzzing-type noise coming from the transmission. This noise occurs as soon as the EGS (TEHCM) "wakes up" when the vehicle is unlocked. This noise is heard regardless of whether the engine is running or not.
2. A clicking noise is heard with the engine running and the either the "P" or "N" position is selected.
CAUSE
1. This noise indicates a normal situation which occurs as soon as the EGS (TECHM) "wakes up"; for example, when the vehicle is unlocked. This noise is heard regardless of whether the engine is running or not.
2. To prevent the solenoid valves in the TECHM from jamming or air collecting in the oil passages, the valves are cycled in a frequent manner. This controlling behavior can be heard in some situations.
Neither of these noises indicate evidence of a fault, nor are they a result of faulty transmission behavior.
Additionally, there is no negative effect on transmission operation or service life.
WARRANTY INFORMATION
This Service Information bulletin is intended to provide technical, diagnostic and/or repair process information only.