Car jerks when shifted into drive, transmission slipping

ANSWER : Hello. Too much transmission fluid sometimes causes slipping in the transmission, but usually causes seals to blow or fail prematurely. It sounds like your car may have a misfire condition. This means that one or more of your spark plugs are not getting an electric spark. It is possible that a tune-up could fix your problem. It would be a good idea for you to have a certified technician, like one from YourMechanic, complete a misfire inspection to determine what is causing your vehicle’s issues.

ANSWER : Hi There,
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. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your transmission.

ANSWER : It is very possible that you could have some internal transmission damage. I would recommend enlisting in the assistance of a qualified transmission professional to inspect your transmission for internal faults. I must warn that this could be a pricy inspection as it may involve the removal and disassembly of the transmission. However, this is a sure fire way to determine if any internal damage has occured. The good news is that if any damage has occured, it can easily be resolved at that time since the transmissoin has already been disassembled.

ANSWER : Hello, thank you for writing in. The color and condition of the transmission fluid should be a huge indicator. Low transmission fluid is one of the leading causes of issues with the transmission. You will want to start by refilling the transmission fluid, following manufacturer directions and specifications on the type and the amount of fluid. If this makes a difference, then you know the lack of good hydraulic fluid in the system was the immediate cause of your problems. This does not always mean that the transmission is not having other issues, as burnt fluid is not a good sign in a vehicle that is only 6 years old. Burnt fluid can also be a sign of how hard the vehicle is being driven. If filling the transmission with fresh fluid does not solve the issue, then the transmission needs to be inspected by a transmission specialist. Unless properly trained, automatic transmissions are incredibly difficult to work on at home.

ANSWER : This may be a result of low transmission fluid or potentially a faulty transmission control module. A faulty transmission control module may cause a delay in acceleration or erratic shifting of gears. 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. I would suggest having a professional from Your Mechanic come to your location to properly diagnose your transmission problem.

ANSWER : Hello – some would say not to flush the transmission at this mileage point, for fear of stirring up debris and clogging shift valves. On the other hand, changing the fluid and filter may improve gear engagement (slow as you note), and improve what’s left of friction surfaces of clutches. To be certain make sure the transmission fluid level is correct. If you need some assistance, I would recommend having your shifting issue diagnosed by a mobile, professional mechanic, such as one from YourMechanic, to diagnose this problem, get an accurate assessment of damage and cost estimate for repairs.

ANSWER : Hi There,
This may be a sign of a faulty MAP sensor as the vehicle responds adversely to a load put on the motor (i.e. putting it in gear, turning on AC or engaging the brakes). The Manifold Absolute Pressure (MAP) sensor senses engine load and generates a signal that is proportional to the amount of vacuum in the intake manifold. The engine computer then uses this information to adjust ignition timing and fuel enrichment. When the engine is working hard, intake vacuum drops as the throttle opens wide. The engine takes in more air, which requires more fuel to keep the air/fuel ratio in balance. When the computer reads a heavy load signal from the MAP sensor, it adjusts the fuel mixture to slightly more rich than normal so the engine can produce more power. The computer will then retard (back off) ignition timing slightly to prevent detonation that can damage the engine and decrease performance. This may also be caused by other closely related components such as a dirty or failing mass air-flow sensor, a faulty throttle position sensor or potentially a vacuum leak. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.

ANSWER : Hello. From what you describe, it would appear that your transmission is beginning to slip. This can be caused by many things. The first thing I would do is check the vehicle’s transmission. Automatic transmission use fluid pressure to operate, and will have all sorts of issues if the fluid is low or dirty. If the fluid checks out, I would then move on to looking at the transmission itself. It may be possible that one of the components, such as a sensor or solenoid may be going out and causing your issue. It may also be possible that the transmission is simply worn out and can no longer hold the engine torque, perhaps due to a worn clutch pack, valve body, or torque converter. In these cases of removal and overhaul of the transmission is required. You may be able to continue driving the vehicle, however, because it may cause the symptoms to worsen over time if the issue is not quickly addressed.