Q: Car jerks and rattles when accelerating until 30 mph

asked by on

My car rattles and jerks while accelerating when the shifts occur up to 30 mph. Also, over 30 it slows down quickly if I release the accelerator. I just moved cross country driving here

My car has 15000 miles.
My car has an automatic transmission.

What you are describing may be a result of a faulty speed sensor, potentially low transmission fluid or a even a faulty transmission control solenoid. As your vehicle travels down the road, the computer analyzes data being sent by vehicle speed sensors and engine speed sensors. Based on this information, the Engine Control Unit (ECU), or the Transmission Control Unit (TCM), executes the appropriate upshifts and downshifts by sending a signal to one of several shift solenoids. These transmission solenoids have spring-loaded plungers inside them, which are wrapped with wire. When this coil of wire receives an electrical charge from the TCM / ECU, it causes these plungers to open, allowing transmission fluid to flow into the valve body and pressurize the desired clutches and bands. When this happens, the transmission changes gears and you continue down the road. The computer controls the transmission solenoid in several ways. If the vehicle is equipped with a dedicated Transmission Control Unit, it can open or close the hydraulic circuit using a direct 12v signal. In some cases, the Engine Control Unit (ECU) can control the solenoid’s plunger by turning the ground circuit on and off. When this is not working properly, this can cause a jerking reaction, a delay in shifting or in some cases may cause the transmission to hesitate in shifting gears. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your transmission.

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. Car jerks and rattles when accelerating until 30 mph

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: Door not closing.

Ford actually issued a recall regarding faulty door latches. I suggest calling your local Ford dealer with the VIN of your vehicle to see if it is covered. If not, a trained mechanic, like one from YourMechanic, can install a...

Q: Do I need alignment after replacing front shocks and struts

Some vehicles have fixed front camber which is typically the only alignment criteria (measure) that would be affected by strut replacement. However, your vehicle does have adjustable camber settings and so, yes, the vehicle would have to be aligned if...

Q: how do I get the wiper switch off 2014 promaster

Hello, thank you for writing in. Typically you want to start by disconnecting the battery and cutting power to the switch. Then you must access the combination (also known as multi-function) switch by removing the dashboard panels and steering column...

Related articles

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...
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...