A/T - 4L60-E/4L65-E/4L70-E Whine/Whistle/Chirp Noise
Bulletin No.: 06-07-30-017ADate: August 16, 2006
TECHNICAL
Subject:
4L60-E, 4L65-E, 4L70-E Automatic Transmission High Pitched Whine, Whistle, Chirp or Buzz Type Noise at 1,500-1,800 RPM (Replace with Updated Torque Converter)
Models:
2005-2006 Cadillac Escalade, Escalade ESV, Escalade EXT
2005 Chevrolet Corvette
2005-2006 Chevrolet Silverado, Silverado SS, SSR
2006 Chevrolet TrailBlazer SS
2005-2006 GMC Sierra, Sierra Denali, Yukon Denali, Yukon Denali XL
2005-2006 Pontiac GTO
2005-2006 HUMMER H2, H2 SUT
with 4L65-E, 4L70-E Automatic Transmission (RPOs M32 or M70)
2007 Chevrolet Avalanche, Suburban, Tahoe
2007 GMC Yukon, Yukon XL
with 4L60-E Automatic Transmission (RPO M30)
Supercede:
This bulletin is being revised to update Transmission RPO usage information in the Parts table. Please discard Corporate Bulletin Number 06-07-30-017 (Section 07 - Automatic Transmission).
Condition
Some customers may comment on a high pitched whistle or whine type noise at approximately 1,500-1,800 rpm while in any forward gear with the torque converter clutch (TCC) disengaged. This noise is typically easier to duplicate when driving up a slight grade when accelerating. This noise will stop when the TCC is engaged. Some 2007 vehicles have been reported to exhibit this noise in 1st gear at approximately 16 km/h (10 mph) with 30-50% TPS on a launch from a stop.
Cause
The torque converter pump blade may cause this condition. A torque converter pump blade revision is expected in production by the end of July, 2006.
Correction
To determine the location of the noise, use the chassis ears with a small acoustic clip-on microphone (such as Radio Shack P/N 33-3013) plugged into the chassis ear amplifier. Drive the vehicle to duplicate the concern using the chassis ears and the Tech 2 to apply and release the TCC. If the noise is coming from the bell housing area only, when the TCC is commanded off, replace the torque converter. If the noise is present with the TCC commanded on, this noise is not caused by the torque converter and torque converter replacement will not correct the condition.
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Parts Information
Warranty Information
For vehicles repaired under warranty, use the table.
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