Having an engine and transmission that work harmoniously is critical for efficient driving. One component that helps both drive systems communicate is the kickdown cable. This device helps the engine relay information on revolutions per minute (RPM) to the automatic transmission and essentially tells it that it's time to shift gears. Like any other component under the hood of your vehicle, it is subject to wear and tear and can wear out or break entirely.
Although the name implies that it should "kick down" gears, the primary role of this component is to shift up into higher gears as the vehicle accelerates. It comprises of rubber and metal and is attached in the transmission and will engage when a gear shift is about to occur. The kickdown gear operates in extreme conditions, which is why it's one of the most commonly replaced parts in the powertrain when shifting issues occur.
Like any component, the kickdown cable will display several warning signs and indicators of wearing out or if it has broken entirely. Being proactive about replacing the kickdown cable before it breaks and causes extensive damage to other transmission components is important. Listed below are a few of the warning signs that a problem with the kickdown cable exists.
1. The transmission shifts hard
An automatic transmission has multiple parts that are engineered to produce a smooth transition from one gear to another. The shift happens at predetermined RPM's and often happens with very little feeling inside the cab. However, when your automatic transmission shifts hard enough for you to feel a jolt in the steering wheel, it's typically not a good warning sign. In most cases, this symptom is caused by a lack of transmission fluid pressure, caused by a leak or low fluid.
However it can also be caused by a faulty or worn out kickdown cable. If the cable is not engaging or is slipping, then it will be very hard to produce a smooth gear change when needed. The cable can be damaged due to aggressive driving where the automatic transmission makes multiple up and down shifts. The more jerking and shaking the transmission does on the road, the more damage is possible to the kickdown cable and other transmission components.
2. The car shifts early and fast
A shift to a higher gear is supposed to be gentle and gradual. This allows the flywheel, transmission gears and the drive shaft to gradually change speed together. However, when the car feels like it's jumping quickly to the next gear, something is wrong internally that needs to be inspected by an experienced transmission specialist. In many cases, this warning sign is caused by a faulty or twisted kickdown cable.
When the vehicle shifts into another gear quickly, there is always the risk of the gears in the transmission getting damaged. However, damage to the engine's flywheel, the input shaft and driveshaft are also possible. As soon as you notice this warning sign, make sure to contact a mechanic as soon as possible to avoid further damage to other engine components.
3. The transmission shifts slow and late
On the opposite side of the spectrum, a slow or late shifting transmission will also be an indication that a problem with the kickdown cable exists. In this scenario, the kickdown cable is typically stretched and will cause a delay in the shifting process. Like the above warning sign, this problem may impact the performance of other, expensive to replace components like the driveshaft and flywheel of the engine.
Anytime you notice any of these warning signs, it's important for you to contact a local ASE certified mechanic that has experience working on automatic transmissions. A faulty or worn out kickdown cable can be replaced rather easily. But, if the cable has broken, it may result in a complete transmission rebuild. Be proactive, and contact a mechanic from YourMechanic.com if you notice any of the above symptoms so they can replace the kickdown cable for you.