Skip the auto shop - Our mechanics make house calls

Q: Truck will shift sometimes then it doesn't shift. If you wait a while it will shift again. We are trying to figure out what's going on

asked by on

Truck will shift sometimes then it doesn't shift. If you wait a while it will shift again. We are trying to figure out what's going on

My car has 128795 miles.
My car has an automatic transmission.

Hi, thanks for writing in. The first thing I recommend is to make sure the ATF (automatic transmission fluid) is full.

Does the transmission shift up a gear or two and stay in that gear, or does it drive fine for a bit, then stop shifting until you turn the car off or sit still with the motor running? Or, do you continue to drive and eventually it begins shifting again. Are there any codes?

What I would do if I were diagnosing your truck would be to connect a scanner and study the data while driving to know what is going on. Without said data and not quite being clear about what is happening, it comes down to solenoids or sensors that the TCM (transmission control module) uses to calculated shift points based on load values determined by the PCM (powertrain control module).

I’m afraid all I can offer you at this point is suggesting you make sure the fluid is full and clean. If it isn’t clean, begin by replacing the filter in the pan and do a transmission fluid exchange, not just pan drop with a drain and fill. This doesn’t get all the ATF out of the transmission, and when there are problems, it pays to be as thorough as possible.

I recommend the following inspection if you should need further assistance: Car hard to shift

Hope this helps and best of luck!

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 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

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  • Home
  • Questions
  • Truck will shift sometimes then it doesn't shift. If you wait a while it will shift again. We are trying to figure out what's going on

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: I've replaced everything from tie rods, upper and lower ball joints, the whole cv axle including cv joints and boots, and I'm stil

Hello, thank you for writing in. The noise you are hearing may be a result of a wheel bearing or a shock issue. There are several tests that can be done while the vehicle is parked, and some while it...

Q: DSG transmission or exhaust issue?

answering

Q: My oil pressure switch went out and haven't been able to start it since, what could be the issue? I have since replaced the part.

Hi, thanks for writing in. I recommend checking the fuel pump fuse and especially the fuel pump relay. Make sure you are getting power from the ignition switch to trigger the fuel pump relay. On newer (incl. 2000) GM vehicles,...

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...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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...