Q: Q: Transmission shifts up and down randomly.

asked by on

While driving highway speeds (60+mph) the transmission seems to 'downshift' and my RPMs jump from 2000 to 3000 which causes the engine to run extremely hard as if I am flooring the pedal. The problem fixes itself when I either slow down enough for the speed to match the RPM displacement or sometimes its possible to accelerate out of the problem. Typically, it seems like an electronic issue and doesn't cause the jeep any other 'visible' physical problems other than overclocking the engine but the last time this occured I felt a jerk as if it really did downshift. I have seen many possible solutions for a variety of problems. I would like to narrow it down to just a few.

My car has 200000 miles.
My car has an automatic transmission.

Hi There, What you are describing sounds like possibly a bad speed sensor or potentially a faulty transmission control module, which also controls the speed sensors. 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. Other functions controlled by the TCM are components such as a kick down switch, traction control system, and cruise control module. Any of these may also affect the way the transmission control module performs and controls the transmission and the shifting of your vehicle. A faulty transmission control module may cause also cause a delay in acceleration or erratic shifting of gears. Lastly, this may also be a result of low transmission fluid. I would suggest having a professional from Your Mechanic come to your location to properly diagnose your transmission 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: Open sunroof during rain-damp front seats, water droplets near switches, damo carpet. Best solution to completely ensure no mold

As long as you totally dry the carpet you should not have a mold issue. If the carpets were completely soaked and floors were flooded then the carpet will need to be removed and the padding (JUTE) under the carpet...

Q: 2003 jeep liberty stuck in reverse, shifter is stuck...but crawling under and trying to manually shift from transmission stuck

Hi there. Based on what you have written above, it is highly probable that the inner linkage has come loose or there is an obstruction within the inner gear set that is causing your problem. Unfortunately, this typically requires dropping...

Q: Car is jerking forward when trying to come to a stop. Jerking started today after filling gas. Service engine soon light is on

Hi There, The check engine light is likely related to your gas cap not locking. This may also cause the jerking reaction as this is connected to the EVAP system in your car. Your car has a small purge valve...

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...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...