The Signs & Symptoms of a Bad Shifter Cableby Robert Moore
A number of current and late model vehicles use cables to link the shifter handle to the transmission. Vehicles with automatic transmission typically have one transmission cable, while vehicles equipped with manual transmissions typically have two shifter cables. The concept of what the shifter cable does is the same regardless of the type of transmission your vehicle is equipped with - the symptoms, on the other hand, are completely different.
What the Shifter Cable Does
Automatic transmissions have a single shift lever that is linked to the manual valve in the valve body of the transmission. This lever is pushed and pulled on a single plane into a number of different positions as you move the shifter handle inside your vehicle. Manual transmissions have two shift levers -- one for vertical movement and one for horizontal movement of the shifter assembly on the transmission. The horizontal lever is pushed or pulled by one cable, moving along a single plane with three positions. The second, or vertical lever typically moves the shifter assembly on the transmission up and down. When you move your shifter toward the front or rear of the vehicle, the shifter cable moves the horizontal lever. Moving your shifter left or right pushes or pulls the other cable, moving the shifter assembly up and down. If you have a six-speed manual transmission, your vehicle may have a third shift cable that moves a lock-out lever. This cable is only used when you press a button or push down on the shift lever to engage reverse.
Why Cables Fail
The most common reason for failure of a shift cable is stretching. It is more common in vehicles with manual transmissions because you move the shifter more frequently; you don't just set it and forget it as you do with an automatic transmission. Cables have also been known to break, or under some circumstances bend, preventing them from moving the shift lever on the transmission into the correct position for the selected gear. If you speed shift either type of transmission or slam gears of a manual transmission, you will cause accelerated wear of a shifter cable.
Symptoms of a Bad Automatic Transmission Shifter Cable
If your vehicle's gear position indicator isn't electronic, you'll notice the indicator needle doesn't line up correctly with the gear you're actually in. As the cable stretches over the life of your vehicle, you may notice that the needle will point to reverse while you're in park, or positioned between reverse and neutral when you're in reverse. Sometimes you'll have a little bit of play in the shifter, even though the transmission is already in gear. When the cable stretches too far, you may not be able to properly engage park, or manually select first gear. When the cable is stretched this much, it can also prevent you from turning the ignition all the way off, or removing the ignition key. Because all automatic transmissions are equipped with a park-neutral safety switch, a stretched cable can prevent the engine from starting in park and neutral or allow it to begin cranking while the transmission is in any other gear.
If your car doesn't seem to want to go into gear at all, it might not be a faulty transmission - It could just be a broken shifter cable. If the cable is broken, you'll be able to move the shifter into any position, but the transmission will stay in the same gear. This may leave you stuck in gear, or even stuck in park depending on when the cable broke. There is a quick test you can perform. If the vehicle doesn't go into any gear, shift the transmission into neutral and try to push the vehicle a couple feet. If you can only rock the vehicle, but your indicator says neutral, the cable is probably broken.
Some automatic shifter cables can be adjusted. If the cable is out of adjustment, you'll experience the same symptoms as you would if the cable was stretched.
If the transmission is stuck in any gear except neutral or park, and is equipped with a park-neutral safety switch on the interior shifter assembly, the vehicle will lunge forward or backward if you try to start the engine.
Parking with a Broken Automatic Shifter Cable
When a shifter cable happens to break, you're pretty lucky if it breaks while the transmission is still in park. It's really just dumb luck when a shifter cable breaks, but it's even dumber luck when it happens while the transmission is in gear. There is a way to remedy this situation without having to lock the keys in your car and leave it vulnerable to theft.
Put the shifter assembly in the park position.
This won't help remedy this situation any, but if your vehicle has the park-neutral safety switch on the interior shifter, you'll need the lever in park to remove the key in a few moments anyway.
Turn the ignition switch off as far off as possible.
Do not attempt to force the ignition into turning any farther than you can, as this will damage the ignition switch, or break your ignition key.
This shuts off the engine, but that doesn't mean the vehicle can't still roll away on you. So, don't hop out of the vehicle just yet.
Engage the parking brake.
Pull upward on the lever in the center console, or push on the pedal that extends from under the dash next to the driver side kick panel. The lever or pedal will lock into place when properly set. This applies pressure to the rear brakes, and if operating correctly will prevent the vehicle from rolling as you exit the vehicle.
Find the shifter assembly on the transmission, and shift it into park.
If your vehicle is front-wheel drive, this lever is likely on the top of the transmission. Look under the hood and find the lever on the transmission with a single cable connected to it, or sitting near it. Turn the shifter lever to place the transmission into park.
If the transmission is on the passenger side of the vehicle, it is common for park to be in the final position when you turn the shifter clockwise. If the transmission is mounted on the driver side, it is common for power to be in the final position when you turn the shifter counterclockwise. If you listen carefully, you can also hear the parking pawl lock into place when you shift it into park.
If your vehicle is rear-wheel drive, it is common for the shift lever to be on either side of the transmission. Park could be to the far left, or far right -- as you look directly at the shifter -- depending on your make and model. If you're not sure which position is park, listen carefully for the metal-on-metal clunk from the parking pawl engaging the output drum as you turn the lever to the far left, or far right.
If you must lift the vehicle, use jack stands to secure the front end in the air. Hydraulic and scissor jacks are only designed to lift the vehicle. If you rely only on the jack to support the vehicles weight, you risk serious injury or death.
Do not crawl under the vehicle if the emergency brake will not lock into place.
Remove the key from the ignition.
Now that the transmission is in park, as well as the shift lever on the inside of your vehicle, you can turn the ignition to the off position, and remove the key. Don't attempt to drive the vehicle without repairing the broken or stretched cable first.
Attempting to put the vehicle into gear from outside the vehicle, or attempting to start the engine with the transmission in gear may result in serious injury or death.
Symptoms of a Bad Manual Transmission Cable
Manual transmission cables can be a little more tricky to diagnose. If the horizontal cable is stretched, you may have issues getting the transmission to seat fully in any gear. This is most notable by a grinding noise when you let off of the clutch since the stretched cable cannot pull or push the lever far enough.
Don't confuse this grinding with with the grinding you often hear when shifting on a worn clutch. When the clutch is worn, the gears will grind as you try to engage a gear. When the cable is stretched, the grinding happens when you release the clutch, even if the shifter inside is pushed all the way forward for odd gears, or pulled backward for even gears and reverse.
If the vertical cable is stretched, you'll get a similar symptom, except it will only be noticeable in gears when the shifter isn't directly forward or backward of the neutral position. Third gear and fourth gear will normally engage and operate as they should since the shift pattern doesn't rely on left or right movement of the shifter. Either cable being stretched will also cause the shifter to be sloppy or have a lot of play -- just like worn bushings on the shifter cables or rod-style linkages.
If either cable is broken, the shifter handle won't return to the neutral position automatically if it isn't in gear. If the horizontal cable is broken, you won't be able to shift into any gear. If the vertical cable is broken, you'll be able to get into 3rd and fourth, but all other gears will seem non-existent. If both cables are broken, you can swivel the shift and any which direction freely without any noise or resistance from the transmission.
In a jam, you may be able to get the vehicle to take off in third gear, and shift into fourth if just the vertical cable is broken.
Robert Moore started writing professionally in 2002. His career started has head writer and Web designer for VFW post 1224 in Hamburg, Michigan. He has prepared business plans, proposals and grant requests. Moore is a state of Michigan-certified mechanic and is pursuing an Associate of Arts in automotive technology from Lansing Community College.