RPM's go from 2000 to 4000?

2003 GMC YUKON
150,000 MILES • V8 • 4WD • AUTOMATIC
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SUZANNEMANGINO
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What does it mean when you are driving 60 MPH on the highway on flat ground with a full load and the RPM's go from 2000 to 4000. Transmission fluid and oil levels are full.
Mar 2, 2009 at 8:01 PM
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SQM
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Hello,

If you did not change the throttle input then it sounds like the transmission is downshifting.
If it does that without any input on your behalf, it can be due to transfer case control module. It can be due to the transfer case 'thinking' you need to be on four wheel low and triggering that.

Transfer Case Shift Control Module is located on the left side of the instrument panel.

I have included the reprograming and replacement procedure for that module (look below).

Please let me know of any questions.
Thank you.

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Sep 20, 2021 at 10:29 AM