Transmission whine/buzz

[Cadillac Tech]

Document ID: 1987733 <HR>
<FORM name=CellHandlerForm onsubmit="javascript: return true;" action=/si/cellHandler.do method=post>#PIP4021B: High Pitch Whine Or Buzz Noise Heard From Under The Vehicle - keywords engine ignition off - (Jun 13, 2007)

<TABLE border=0><TBODY><TR><TD vAlign=top width=100>Subject:</TD><TD vAlign=top>High Pitch Whine or Buzz Noise Heard From Under The Vehicle </TD></TR></TBODY></TABLE>

<TABLE border=0><TBODY><TR><TD vAlign=top width=100>Models:</TD><TD vAlign=top>2007 Cadillac Escalade, Escalade ESV, Escalade EXT, STS, SRX</TD></TR></TBODY></TABLE>
<TABLE border=0><TBODY><TR><TD vAlign=top width=100></TD><TD vAlign=top>2006-2007 Cadillac XLR, XLR-V</TD></TR></TBODY></TABLE>
<TABLE border=0><TBODY><TR><TD vAlign=top width=100></TD><TD vAlign=top>2006-2007 Chevrolet Corvette</TD></TR></TBODY></TABLE>
<TABLE border=0><TBODY><TR><TD vAlign=top width=100></TD><TD vAlign=top>2007 Chevrolet Silverado</TD></TR></TBODY></TABLE>
<TABLE border=0><TBODY><TR><TD vAlign=top width=100></TD><TD vAlign=top>2007 GMC Sierra, Yukon, Yukon Denali, Yukon XL</TD></TR></TBODY></TABLE>
<TABLE border=0><TBODY><TR><TD vAlign=top width=100></TD><TD vAlign=top>Equipped With a 6L50, 6L80 or 6L90 Transmission RPO MYB, MYC or MYD</TD></TR></TBODY></TABLE>​

<HR>This PI is being superseded to update models. Please discard PIP4021A.

<HR>The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1987733&from=bcpi#ss1-1987733">Condition/Concern:​

Customers may comment on hearing a high pitched tone or whine type noise heard from the vehicle either with the key on and engine off or for up to one minute after the vehicle has been shut off. The noise should be heard from outside the vehicle only or with a window open and be most noticeable in an enclosed area i.e. garage area.
Recommendation/Instructions:​

The whine/tone is caused by the internal transmission solenoids being commanded to minimum line pressure by the TCM. This noise should be considered an operating characteristic and no repairs should be attempted.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
<TABLE width="95%"><TBODY><TR><TD align=left width="80%">GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

​

</TD><TD align=middle width=42> </TD><TD align=middle width=167>WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

​

</TD></TR></TBODY></TABLE>​

© 2009 General Motors Corporation. All rights reserved.
</FORM>