How to Change a Clutch | Auto Mechanics 101

Replacing the clutch in your vehicle is a lengthy process, but it’s not that hard at all.

I spend a lot of time perusing used car websites, not because I am looking to purchase, but only because it is interesting to see the types of cars and trucks folks out there are trying to get rid of. One of the things that always piques my interest is when I see a vehicle that says “Mechanic’s Special” or something to that effect because often, these vehicles are available for next to nothing. Sometimes, that excellent deal evaporates in a pile of expensive and hard-to-find parts, but other times you can get a great deal on a vehicle that simply needs a little love.

A friend bought a vehicle a while back that was not running. The owner explained that the clutch had gone out and repair shops wouldn’t touch it for less than $1,500. The car wasn’t in fantastic shape, but in running condition, it would be worth at least three times the cost of the repair, but the owner just couldn’t justify spending the money, so he dumped the car.

Rather than pay the local shop’s labor rates to change the clutch, my friend did the job himself. Replacing a clutch may seem like a difficult task to do in your driveway, but it’s not really that complicated. Once you understand how the clutch works, disassembling and replacing it is much easier, and it’s a task you can do yourself and save quite a bit of money.

You should have a high-quality repair manual for your specific vehicle before tackling a clutch replacement. While most vehicles have a similar repair procedure, each has unique steps that must be followed, and a shop manual is a great way to help identify the parts and find out the correct torque specifications.

What is a Clutch?

The clutch is a disc of friction material that applies pressure to the flywheel to connect the engine’s rotational forces through the transmission and drive wheels. When the clutch pedal is depressed, the pressure plate releases pressure from the flywheel and lets the transmission spin freely.

Once you select the next gear and release the clutch pedal, the pressure plate resumes applying force to the clutch and connects the engine’s rotational energy with the transmission. This is the basic way that all manual transmission clutches function.

Why Does the Clutch Go Out?

Over time, the clutch disc’s friction material wears away, just like the pads on your disc brakes. Drivers who tend to hold the clutch pedal down slightly as they accelerate wear clutches faster than drivers who quickly release the pedal. Moreover, hard shifting can cause hot spots on the flywheel, leading to uneven clutch disc wear. Leaks from the engine or transmission can also cause the clutch disc to become saturated, causing it to fail.

How do You Know When the Clutch is Bad?

The first sign that the clutch is going bad is slipping in gear when accelerating. Engine RPM will increase, but the car will not accelerate as quickly as it should. You may notice a burning chemical smell as the clutch disc surface heats up on the flywheel. Eventually, the clutch will not hold engine rotation, and the car will have to be towed. It’s a good idea to plan on replacing your clutch before it fails completely.

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Parts of a Clutch

Today, most clutch assemblies are hydraulically actuated, though many vintage cars will use mechanical linkages to operate the pressure plate. Understanding what each part is called and how they work together makes it easier to understand how to change a clutch yourself.

Flywheel

The flywheel is a heavy steel disc that attaches to the engine crankshaft at the back of the engine block. The flywheel serves three functions: it provides inertial energy for engine rotation, provides a toothed gear to engage the starter motor, and allows a flat friction surface for the clutch to engage against.

Clutch Disc

The clutch disc is a metal disc that holds a friction material, much like the pads in a disc brake system. Springs at the center of the clutch disc dampen engine vibration and help provide smooth engagement and release from the flywheel. The clutch disc is fixed in place on the splines of the input shaft of the transmission.

Pressure Plate

The pressure plate bolts to the flywheel and houses the clutch disc. It serves two functions—keeping the clutch disc centralized and providing the force to release and depress it.

Throwout Bearing

The throwout bearing provides the connection between the stationary pedal linkage and the rotating clutch face. The throwout bearing is also called a clutch release bearing. It is usually held in place with a forked metal arm the pedal linkage/slave cylinder presses against to operate the clutch.

Pilot Bearing

Not all manual transmissions use a pilot bearing, but it is an important component to remember to inspect when replacing the clutch. The pilot bearing typically sits in a recess at the end of the crankshaft and provides a low-friction rotating point for the transmission input shaft nose.

How Much Does it Cost to Replace a Clutch?

You can save a big chunk of money by replacing the clutch yourself. Most cars and trucks that use a manual transmission have a clutch replacement kit available that includes the replacement parts and a special alignment tool. A clutch kit will cost between $150 on the low end to $500 for some of the more expensive factory replacement parts. Custom high-performance clutch kits are also available that can cost several thousand dollars. You’ll spend an average of $1,000 less by completing a clutch replacement yourself.

How Long Does it Take?

Most clutch replacement jobs will only take a few hours of labor. The most time-consuming part of the job is machine work that is required unless replacing certain components. The average home mechanic with hand tools and a couple of floor jacks can complete a clutch in a weekend or less.

Front-Wheel Drive vs. Rear-Wheel Drive Clutch Replacement

You’ll need to replace a clutch sooner or later, regardless of whether your car is front-drive or rear-drive. The main difference between the two designs is that RWD vehicles typically have more room to work around. Most of the steps are the same regardless of the drivetrain.

It may be necessary to remove the exhaust on either FWD or RWD vehicles to create clearance. Use plenty of penetrating oil on exhaust bolts before trying to remove them to prevent broken fasteners. Don’t let the weight of the transmission sit on the exhaust pipes because you can crack manifolds, bend the exhaust, and drop the transmission.

Special Tools and Steps for FWD

Most FWD vehicles will require a ball joint separator or a special tool for removing axle shafts. Read your repair manual carefully and inspect these parts as you remove them. It’s easier to replace worn-out stuff while it’s already apart. It’s also a good idea to purchase or fabricate an engine stand that rests on the suspension uprights to support the engine from above. Many FWD vehicles use engine mounts that attach to the transmission, so you need to support the motor during the process.

Considerations for RWD Clutch Replacement

When removing the transmission on an RWD vehicle, you’ll need to remove the prop shaft, also called the drive shaft. Most RWD vehicles use U-joints in the prop shaft. Inspect these for wear and replace them if needed. Save yourself a ton of hassle and take it to a drive shaft repair shop for U-joint replacement and balancing. It’s cheap and way less hassle.

You also will need to support the engine when replacing a clutch in an RWD vehicle. Most of the time, you can use a 2×4 woodblock and a floor jack positioned beneath the oil pan to raise and lower the rear of the engine and support it while the transmission comes out. An engine hoist with front-rear leveling is also useful when replacing a clutch.

Steps to Replace a Clutch

Raise and safely support the vehicle so that it is as level as possible. Use good-quality vehicle stands rated to handle the weight of your vehicle. Never work under a vehicle supported only by a floor jack. Also, always test the position of the jack stands by firmly shaking the vehicle before working beneath it. They shouldn’t move if the vehicle is properly supported.

1. Disconnect Accessories

Your repair manual will provide instructions on the process for disconnecting the shifter from the transmission. In most vehicles, the shifter assembly will unbolt and lay aside. It is a great time to replace bushings in your shifter to get the correct tension when you put it all back together. Disconnect any electrical connections, vacuum lines, and the speedometer cable if your transmission has one. Disconnect and remove the starter motor.

2. Remove Engine Bolts

Locate the bolts that connect the rear of the engine to the bell housing of the transmission and remove all of them. Don’t forget to have an organizational system for nuts and bolts. A great tip is to use cardboard egg crates. A magic marker works great for labeling where those fasteners came from and makes reassembly faster.

3. Remove Drive Assembly

Remove the drive axle or prop shaft according to your vehicle service manual. Use a rag to keep transmission fluid from running out of the output. Place a transmission jack or a floor jack with a cradle beneath the transmission and raise it enough to take tension off the transmission crossmember.

4. Take Out the Crossmember

Remove the transmission mount-to-crossmember bolts first, remove the crossmember-to-subframe bolts, and make sure the transmission remains balanced and supported throughout. Then, remove the crossmember to provide room to lower the transmission. It’s a good idea to replace the transmission mount any time you disassemble it. The part is usually inexpensive.

5. Remove the Transmission

Carefully lower the floor jack holding the transmission and guide the unit away from the engine. It may be necessary to slightly raise the engine’s front to help the transmission and engine separate. Once the transmission input shaft is clear of the rear of the engine, move the transmission out from beneath the vehicle and place it on a stand for disassembly.

Inspecting the Clutch Components

With the transmission removed from the vehicle, the flywheel can be pulled with the pressure plate and clutch assembly. Unbolt the pressure plate assembly from the flywheel and separate the clutch disc.

You will want to inspect the flywheel carefully before putting it back in. The first things you should look for are scorch marks or cracks in the flywheel’s surface where the clutch comes into contact. Also, look for grooves in the metal deeper than a fingernail. These are signs of a potentially faulty flywheel.

The other thing to look at is the toothed gear around the perimeter. This is called the ring gear, and it’s usually welded or pressed to the flywheel. The teeth engage in the gear of the starter to turn the engine and start the vehicle. If the teeth are worn at angles, chipped, or broken, the ring gear will need to be replaced. Most machine shops will handle this repair for you.

Putting it Back Together

After you purchase a clutch kit for your vehicle, you need to take the flywheel to a machine shop to check the thickness of the contact surface. Your clutch must have enough surface to grip against to function correctly, and just like your brakes, the surface must be smooth. After you bolt the flywheel back into place, wipe the surface down with alcohol to remove fingerprints and ensures the friction surface is grippy.

Using the Pilot Tool

Your clutch kit includes a funny-looking plastic piece called a pilot tool. You’ll use the pilot tool to align the splines on the clutch with the input shaft. Once you align and torque-screw the flywheel according to the specifications in your service manual, you pass the clutch disc onto the tool, then set it in place against the pilot bearing. The pressure plate is then aligned against the flywheel and torqued to specification. Slide the alignment tool out of the assembly.

The Trick to Installing a Transmission

Now that you are ready to refit the transmission, the simplest-seeming thing is often where DIYers get stuck- engaging the transmission. The trick is to get the input shaft gear to align with the clutch disc held in place by the pressure plate while moving the transmission into place. Sounds difficult? It is. But be patient, take your time, and don’t force anything, and you’ll succeed in getting the input shaft to align with the clutch disc and slide into the pilot bearing. It makes a satisfying clang when the bell housing contacts the rear of the engine.

Pro Tip:

FWD & RWD installations are much easier when you can manipulate the angle of the engine as the transmission is put in place. A good-quality engine hoist is a great tool to have on hand. This is a job you certainly can do by yourself, but it’s a great opportunity to get your friends involved in the things you love. An extra set of hands certainly comes in handy on tasks like replacing the clutch.

Wrap it Up

Now that your clutch is installed and the transmission is back in place, you simply reverse the process you went through to disassemble stuff. Refit the axle shafts or prop shaft, bolt in the transmission mount, and then torque the crossmember to the specifications in your repair manual.

Hand-thread the bolts connecting the engine to the bell housing and the starter bolts, then torque in sequence according to the repair manual for your vehicle. Don’t forget to reconnect the electrical plugs, vacuum lines, and speedometer.

Last Words

Replacing the clutch in your vehicle is an awesome opportunity to gain courage doing something a repair shop charges a lot of money to do. Moreover, it’s a big confidence booster, and you’ll have a more personal connection with your car, knowing that you can fix an essential component in the driveline.

Finally, you should find the most comprehensive repair manual on the market for your vehicle before starting any serious project. It will help you find the parts you need and guide you through the process. Have fun!