Q: Engine revved in drive - 2006 Chevrolet Avalanche 2500

asked by on

My truck’s engine revved freely when the transmission was in Drive, as if it were in Neutral. On the shoulder of the road, I coasted to a stop, then shifted into Park, and released the brake pedal. At that point, my truck started rolling forward, downhill, I assume because the transfer case shifted into neutral. The indicator was not on. I turned off the engine. I had a code reader, but it did not show any codes at all.

I restarted the engine and shifted into Drive, at which time I felt the transmission engage (the transfer case must have engaged from neutral). Gradually I accelerated and then drove down the highway for ¼ mile. When I released the accelerator pedal, the transfer case shifted into neutral again, engine revving when it was still in Drive. After I coasted to a stop on the shoulder, I pressed the 4WD high and then felt the transfer case engage, pressed 2WD hi and felt the transfer case disengaged; however, now it was in 2WD instead of neutral.

Gradually accelerating I drove down the highway and when I released the gas pedal the transfer case shifted into neutral again while the engine was revving with the truck in Drive. Coasted to a stop again and repeated the sequence. Shifted into 3rd, gradually accelerated, and drove some more and the transfer case remained in 2WD high. On the shoulder I stopped slowly, turned off the truck, restarted, and shifted into Drive, gradually accelerated and drove some more - released pedal and transfer case shifted once again into neutral. In your assessment, what is causing this problem and what do I do to correct it?

This sounds like the transfer case isn’t completely engaging selected gears (High/Low, 2/4wheel drive). There is a GM Service Bulletin on this issue - TSB Reference #3424. Check with your dealer on this one.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Engine revved in drive - 2006 Chevrolet Avalanche 2500

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Transfer case shift motor

Hello. C0327 is the trouble code for a malfunction with the transfer case encoder motor as you alluded. This is the electric motor that allows the transfer case to engage into 4wd mode. This code is commonly caused by water...

Q: no acceleration when pushing the gas pedal down (even to the floor)

This may be related to a faulty mass air flow sensor or potentially a bad throttle position sensor. The mass air flow sensor monitors air as it enters the intake system allowing for the proper amount of fuel to be...

Q: The RPM's on my car are increasing more quickly than I am accelerating

Hi there. If the O/D light was blinking, then that typically means that the computer is seeing a transmission problem. It can be as simple as a speed sensor or as complicated as a serious internal transmission failure. This can...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.