Q: Q: Transmission shifts up and down randomly.

asked by on

The truck shifts in and out of overdrive to a lower gear randomly

My car has 105,000 miles.
My car has an automatic transmission.

This may be a result of a faulty transmission control module. A faulty transmission control module may cause a delay in acceleration or erratic shifting of gears. The transmission control module has various sensors such as vehicle speed sensors, wheel speed sensors, throttle position sensors, turbine speed sensor, and transmission fluid temperature sensors that all direct information to it in order for it to perform it’s function. A kick down switch is also operated by the TCM which controls when the transmission downshifts. When this is faulty, this may cause the erratic downshifting out of overdrive you describe. Any of these may also affect the way the transmission control module performs and controls the transmission and the shifting of your vehicle. I would suggest having a professional from Your Mechanic come to your location to properly diagnose your transmission shifting problem.

Was this answer helpful?
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. Q: Transmission shifts up and down randomly.

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: Drive-by-wire throttle problem

Hello. The symptoms you describe may be caused by issues with the throttle body or with the idle air control valve. The drive by wire system controls an electric throttle body which feeds the engine air. If the throttle body...

Q: Truck cuts off when stopping

Hello. Stalling at stops can be caused by many things. A few common causes are: faulty idle air control valve vacuum leak fuel or engine management issue The most common of these is a failed idle air...

Q: Q: Idle fluctuates and then stalls.

Hi There, It sounds like you may have a vacuum leak or potentially a dirty or faulty idle control valve. High idle speeds or in some cases rough idle, stalling and hissing sounds are common signs of a vacuum leak....

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...