Q: Transmission

asked by on

Hello.

I drive a Volkswagen Passat 2007 model. When i engage the gear on drive or reverse, the car jerks forward on D and backward on R. However, none of this problem is experienced when on motion with the D. May i know what you think the problem might be and a possible solution.

Thanks in advance.

Hello There, This may be a sign of low transmission fluid or a faulty transmission control solenoid. As you’re going down the road, the car’s 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 upshift / downshift by sending a signal to one of several shift solenoids. These transmission solenoids have a spring-loaded plunger inside, which are wrapped with wire. When this coil of wire receives an electrical charge from the TCM / ECU, it causes the plunger 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 car’s 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. Or, the Engine Control Unit can control the solenoid’s plunger by turning the ground circuit on and off. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your transmission.

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

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!
  1. Home
  2. Questions
  3. Transmission

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: Bought it yesterday. Check engine light is on

The most common reason for that fault to be set in this particular car is unfortunately a failed catalytic converter. Misfiring, which can be caused by faulty spark plugs or ignition coils, can cause damage to the catalytic converter, which...

Q: Honda odessy doesn't blow cold

Hi There, It sounds like you may have a bad AC condenser. The A/C uses a compressor to turn a refrigerant gas, usually Freon, into a liquid concentrating its heat. In this state, it passes through conductive pipes in a...

Q: Is it worth replacing my throttle body to try to eliminate the epc light?

When the EPC light comes on, it often a problem in the throttle body, but not necessarily. If the light is on, it means the controller will have stored codes to assist in the diagnosis. It's not something you want...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...