Clutches are normally associated with a manual transmission. However, they are not actually integral to the inner workings of the manual transmission itself. Clutches are simply the connection point between the engine and the transmission. When you push the clutch in, you are breaking this connection between the two. When you let the clutch out, you are reconnecting the engine to the transmission. The re-connection from a stop has to happen in a modulated way, as to not stall the engine.

Clutches generally fail in one of two ways. The first way happens when the clutch fails to connect to the point where the vehicle won’t move or only partially moves when you let the clutch out. The other way the clutch can fail is when it fails to disconnect with the clutch pushed in. Sometimes, this is a mild fail with glitchy shifting and sometimes you can’t miss the symptom since the car is hardly driveable. When a clutch fails to disconnect completely, you will experience difficulty getting the shifter into any gear. First gear and reverse will be the first to resist with a partially disconnecting clutch. Either of these two failures don’t always necessitate a major or complete clutch replacement. Often times a minimal clutch repair, adjustment and/or clutch maintenance is all that needs to happen.

Signs Your Clutch is Not Fully Engaging or Engaging At All:

• When accelerating, the speed of the vehicle does not seem to follow the engine speed proportionally
• Burning smell
• Drop in gas mileage
• Extremely soft or extremely hard clutch pedal
• Clutch does not seem to fully engage until the pedal is all the way out
• Car does not want to move at all when letting out the clutch

Signs That Your Clutch is Not Fully Disengaging or Disengaging At All:

• Difficulty shifting from gear to gear (usually affects all gear changes)
• Grinding or scraping noise between gears (generally more pronounced in 1st gear or reverse)
• Although getting into reverse is generally more difficult, when a clutch is not fully disengaging, reverse can become next to impossible

Other Signs a Clutch Issue Might Be Present:

• Chattering or jerking sensation when releasing the clutch pedal
• Crunching noises or a “hard” clutch pedal

Tip for shifting into reverse (as reverse is generally non-synchronized:) Always move the shifter into a forward gear before moving to reverse

Styles of Clutch Control:

Hydraulic Type: Operates much like a brake system. There is a clutch master cylinder (connected to the clutch pedal), clutch slave cylinder (connected to the clutch fork) and hydraulic lines that connect the two. Hydraulic tends to be the most common we see from vehicle manufacturers. It is more common with newer model vehicles.

Cable Type: Simply put, a cable connects the clutch pedal to the clutch fork. This is the next most common type used by automobile manufacturers.

Linkage Type: Uses a series of rods and pivot points to connect the clutch pedal to the clutch fork. Less commonly or hardly used any more, it is generally associated with older vehicles. Linkage types tend to wear out, need repair and frequent adjustment.

All three styles generally have some sort of adjustment that can be performed. As simple as they seem to operate, we see a considerable amount of people that get a major transmission replacement or a major clutch repair, when all they needed was a minor clutch adjustment and/or repair.

What to do When You Need a Major Clutch Replacement:

Most mechanics in Phoenix, AZ will tell you they are happy to replace your clutch, but do they do so every day? The operation of a clutch seems simple to most, but that’s just the problem. Technicians are guilty of overlooking simple small details that make a clutch last long and operate great. Things like the right type of grease used on the clutch splines or replacing a scarred bearing retainer on the front of the transmission. Often times, when we redo someone else’s deficient clutch replacement, we find a bearing retainer issue. If you’re not a transmission shop, you generally don’t have the capability to repair the front of the transmission where the clutch release bearing rides, so it won’t be addressed properly. They simply clean it up and shoehorn it back together. That’s an automotive generalist common mistake. Another common mistake is a damaged transmission input shaft at the pilot bearing race surface. With no capability or experience, again, they clean it up with some emery cloth and shoehorn it back together. The results of a deficient clutch replacement is a vehicle that’s now annoying to drive.

Humans Are Adaptive

People can quickly adapt to a bad clutch not realizing it’s causing knee and back problems. We get in some of these cars and trucks where the clutch was recently replaced and can’t believe how badly the clutch pedal feels. The clutch pedal is too hard, chatters when releasing the clutch pedal, or the engagement height is wrong. The engagement point is usually too high or too low.

Other Clutch Buzz Words:

Clutch Fork: This is a lever or leverage at the clutch that is used to compress the group of extremely strong springs in the clutch pressure plate. They can wear out specifically at the pivot point or get damaged when a clutch release bearing goes bad. The clutch fork should be inspected for possibility of replacement with any major clutch repair where the transmission is removed.

Clutch Fork Pivot Ball: This is the pivot point for the clutch fork. Replacement of this ball should almost always be considered with any major clutch repair where the transmission is removed. This is a small detail, but some miss it and the clutch performance suffers.

Bearing Retainer: The bearing retainer is the hollow tube mounted to and/or integral to the front of the transmission. The bearing retainer guides the release bearing through the release stroke. The release bearing, also known as the throw out bearing, slides on this bearing retainer. There is an intense amount of force at the release bearing and the bearing retainer can and does often wear out. They often get overlooked or neglected with major clutch replacements. Major clutch repair is where the transmission is removed. The bearing retainer is an extra detail that slows the technician down, so they might just look the other way. Furthermore, in many cases the automotive generalist technician does not have the tools or capability to address the bearing retainer, so it does not get repaired or replaced. It is imperative that the surface of the bearing retainer is not damaged, scored, scarred or worn down for clutch smoothness and clutch longevity. This greatly affects pedal feel and release bearing life.

Release Bearing (aka Throw Out Bearing): The release bearing is sandwiched between the clutch fork and clutch pressure plate. There are different styles of release bearings. The release bearing is a failure point and should always be replaced with a high quality bearing. Not a cheap aftermarket bearing. If it fails, the whole job gets redone and that may be just out of warranty. So you end up paying twice.

Pilot Bearing: The pilot bearing fits in the back of the engine’s crank shaft. It is crucial for support of the input shaft of the transmission. A deteriorated pilot bearing is the cause for a significant number of transmission shifting issues. Hands down, this is another crucial failure point and should be replaced with any major clutch repair where the transmission has to be removed.

Clutch Disc: The clutch disc is the actual friction material in the clutch assembly. It is an item that does wear out, much like a brake pad. It’s also the reason some people get more mileage out of their clutch than others. It comes down to driver habits and technique.

Pressure Plate: The pressure plate is mounted to the engine’s flywheel. The pressure plate is loaded with powerful springs. With these springs, the pressure plate sandwiches the clutch disc to the flywheel. These are almost always replaced with any major clutch repair where the transmission is removed. This is because the springs wear out and the application surface wears out as well.

Flywheel: Mounted to the engine crankshaft, this is where the clutch disc rides. Much like a brake rotor, the flywheel should be machined with a proper clutch replacement. In some instances, the flywheel should be replaced in lieu of being machined. This is depending on application and condition of wear on the flywheel. This is an area where some like to skip out or cut corners. Addressing the flywheel should always be a topic of discussion with a clutch repair.

Dual Mass Flywheel: The dual mass flywheel is becoming more common. This type of flywheel is built in two parts connected by a spring mechanism that dampens the shock associated with the clutch engagement. Traditionally, damper springs were located in the clutch disc and not in a dual mass flywheel. Because of the dual mass flywheel construction they are either unable to be machined and/or difficult to machine. Created for creature comfort in the vehicle, they often times add considerable expense to a clutch replacement. In some instances for cost savings, dual mass flywheels can be converted back to a traditional set up with the damper springs in the clutch disc.

Clutch Master Cylinder: Much like a brake master cylinder, it is directly connected to the clutch pedal and sends hydraulic pressure to the clutch slave cylinder down at the clutch. When replacing the clutch master cylinder, we often recommend that they are replaced in combination with the slave cylinder. This is not always necessary, but a best practice for a solid repair.

Clutch Slave Cylinder: Much like a brake wheel cylinder, it’s directly connected to the clutch fork or release bearing. When replacing clutch slave cylinders, we often recommend they are replaced in combination with the clutch master cylinder. This is not always necessary, but a best practice for the ideal repair.

Clutch Pedal Travel: The window of distance between the floorboard and where the clutch pedal rests without your foot on the pedal. Typically there should be about 1” of free travel when just starting to push the clutch in before you feel resistance and there should be 1” to 2” of room before the clutch is at the floorboard when the clutch is disengaged. As a clutch wears, the measurements change if not adjusted. A worn clutch will be right at the top of this window. Some types of clutches are self adjusting for this wear, while others are not.