Q: Why is my auto transmission down shifting to the wrong gear when decelerating?

asked by on

When decelerating through 20 mph the automatic transmission shifts into a lower gear that causes the car to lurch/jerk. It only happens when passing downward through 20 mph and it feels like the car drops into first gear at a speed to high for that gear.

My car has 115000 miles.
My car has an automatic transmission.

Improper shifting, either up or down, can be caused by a few different issues. If the transmission fluid condition or level are not correct, this can cause erratic shifting. Servicing the transmission may resolve the issue. Other causes can be the transmission fluid pressure sensor. If the pressure sensor is faulty, the engine/transmission control unit can cause erratic shifting, even skip gears when up or down shifting. Also, the transmission temperature sensor can also be at fault which is a common issue with this vehicle and transmission. I owned the exact same vehicle for several years. Have a certified technician look into the transmission shifting issues to isolate the correct cause.

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. Why is my auto transmission down shifting to the wrong gear when decelerating?

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: Q: The check engine light is on.

Have your vehicle's computer checked to see what caused the check engine light to come on. This will give you a starting place for diagnostics. Most of the time if the battery was running low on a charge, when installing...

Q: Window chips damaging driver side window.

Hello. In most cases, scratches on automotive glass can be difficult to remove if they are deep. If they are shallow, you maybe able to use a bit of metal, or specialized glass polish, to buff out the scratches by...

Q: Brake light warning and Stabikitrack lights continue to come in when driving.

Hi there, thanks for writing in about your 2009 Buick Enclave. You may have one or more wheel speed sensors giving erratic readings. I would recommend having the system scanned to get the codes to see what sensor is causing...

Related articles

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...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...