Shuddering, Slipping and Safe Mode — How to Recognise Problems with Your Torque Converter

Most automatic transmission systems are very reliable and can be expected to last a long time. If they do go wrong, it can often be traced back to issues with the internal torque converter. What is this, how does it work and what type of problem could materialise?

Torque Converter in Action

The torque converter is a very clever device that sits in between the engine and transmission. It takes the place of the clutch pedal and associated mechanism on a manual car and controls the output from the engine. In short, it makes sure that the engine's torque is kept at bay when the vehicle is stationary and is allowed to flow through to the transmission when the car is in motion. Furthermore, it regulates the amount of torque supplied based on road conditions and forward speed.

How It Works

Inside the torque converter are three crucial parts — a turbine, a stator and a pump. The device will turn at the same speed as the engine's flywheel, and as the pump spins, it will channel transmission fluid towards the outside of the casing. The faster it goes, the further the fluid moves and the greater the vacuum in its place. This draws even more fluid into the turbine (or output shaft), which will then cause the transmission to spin and move the car. It's a little more involved than that, but in essence, that explains how the torque converter can play such a crucial role in an automatic transmission.


Obviously, there are many moving parts within the converter, and they may eventually begin to malfunction. If so, this part will not be able to generate hydraulic pressure as smoothly as it should, and the system may start to slip, shudder or unexpectedly disengage.


You may notice issues when you first start the car in the morning or when you are out on the open road. The transmission may shudder and cause a great deal of vibration, but crucially, performance will be very inconsistent.


Heat may build up in the casing as well, and if it gets too bad, the vehicle may shift into 'safe' mode. When this happens, you will only have one slow forward gear and will need to limp to a mechanic.

Leaking Fluid

Special seals within the torque converter can also degrade with time, and as they do, fluid may leak out. When this happens, you won't have enough fluid in the system, which could lead to damage and a further decline in performance.

Quick Action

At the first signs of a potential issue with the automatic transmission, get on the phone and make an appointment with a mechanic who offers auto transmission repair services.