Ace Clutch and Gearbox

When a clutch is working smoothly, you have complete control over the gears. You decide when to change gear and which gear to select. You are always in control and always aware of which gear you’re in.

 

When purchasing a vehicle, many people want the control that a manual transmission provides. A standard ‘stick shift’ allows the driver to have fun, at least on the open road. But around town or when in heavy stop-and-go traffic, the driver, having to constantly ride the clutch and change gears can be a real pain – especially if the clutch is acting up.

 

Because clutches use changes in friction to modulate the transfer of torque between engine and transmission, they are subject to wear in everyday use. A very good clutch, when used by an expert driver, can last hundreds of thousands of miles / kilometres, whereas weak clutches or inexperienced drivers can lead to more frequent clutch repair or clutch replacement.

 

Clutch problems can occur at almost any mileage on a vehicle and for varied different reasons. When the clutch pedal is released and the clutch disc rubs against the flywheel and pressure plate, it generates a lot of friction and heat. This happens to absorb the shock loading that would otherwise jolt the drive train every time the transmission was put into gear or changed.

 

What happens when a clutch has problems?

No clutch was made to last forever. The disc wears as the miles accumulate. City driving and sitting in traffic with lots of shifting is always harder on the clutch than motorway driving. Aggressive driving, pulling trailors or simply leaving your foot resting on the clutch as you drive can also accelerate clutch wear.

 

The worst thing a driver can do is leave their foot resting on the clutch as they drive. This is known as ‘riding the clutch’.

Slipping the clutch constantly when starting out or driving will send the temperature of the clutch soaring. When the temperature rises this causes the facings get too hot, they may start to burn giving off a burning odor. As the clutch isn’t given time to cool, the disc may be ruined along with the flywheel and/or pressure plate.

 

When a clutch starts to slip, it  will be most noticeable when the engine is under load, i.e., when starting out ,when accelerating up a hill or passing another vehicle The more the clutch slips, the higher the temperature will get and the more it wears. This accelerates the problem even more and may result in additional damage to the flywheel and pressure plate.

 

Another cause of clutch failure is oil contamination from a leaky rear main crankshaft seal, transmission input shaft seal or engine oil leak. Oil on the clutch facings will cause them to slip and grab unevenly. The result is typically chattering and jerking when the clutch is first engaged, and slipping when the clutch is under load.

 

Oftentimes, an apparent clutch problem really isn’t the clutch, but the clutch linkage or something else. Many late-model vehicles have a hydraulic clutch linkage with a master cylinder attached to the clutch pedal and a slave cylinder on the bellhousing. The internal piston seals on the master and slave cylinder can develop leaks that allow a loss of pressure when the clutch pedal is depressed. This may prevent the clutch from disengaging or allow it to engage prematurely (as when sitting at a stop light with the pedal all the way in).

 

The pedal may also feel soft and have less than normal resistance. Slave cylinders develop leaks more often than master cylinders because the slave cylinder is the lowest point in the system. Any rust or dirt in the hydraulic fluid is therefore more apt to settle in the slave cylinder where it can cause seal problems.

 

Dual Mass Flywheels

Some vehicles use a second set of springs in a two-piece “dual mass” flywheel. A dual mass flywheel has a series of springs mounted sideways between the primary and secondary flywheels. This provides more vibration dampening and eliminates excessive transmission gear rattle for smoother clutch engagement and operation.

 

Dual mass flywheels can be expensive to replace. Because of  this, Ace Clutch and Gearbox can replace the Dual Mass flywheel to a one-piece solid flywheel that can be installed in place of an original equipment dual mass flywheel. A solid flywheel can save you some money as it will not need to be replaced.

 

Diagnosis

Diagnosing clutch problems is difficult unless you have been trained because a lot of different problems can cause the same kind of symptoms. Chattering when the clutch is engaged can also be caused by a warped or grooved flywheel, missing flywheel dowel pins, a worn pilot bearing/bushing, a worn bearing retainer, worn or damaged clutch disc or input shaft splines, bent or broken drive straps on the clutch, a bent or distorted clutch disc, a loose clutch cover or even missing flywheel dowel pins.

External causes of clutch chatter include loose or broken engine or transmission mounts, misalignment of the chassis and drivetrain components, worn or damaged U-joints or CV joints, a loose transmission crossmember, a worn or bent release fork, or loose rear left spring bushings or spring U-bolt nuts.

 

Clutch won't release

If the clutch does not release completely when the clutch pedal is fully depressed, the disc will continue to turn the input shaft. This may prevent the driver from shifting the transmission from neutral into gear, cause grinding when the gears are changed, or cause the engine to stall when coming to a stop.

 

A clutch that won’t release may have a misadjusted linkage, a broken or stretched release cable, a leaky or defective slave or master clutch cylinder, air in the hydraulic line or cylinders, corroded, damaged or improperly lubricated input shaft splines, a worn pilot bearing/bushing, a worn bearing retainer, bent or worn release fork or pivot ball, bent clutch drive straps, bent or distorted clutch disc, a clutch disc that was installed backwards, or mismatched clutch components (if the clutch was just replaced).

 

Other things that can cause the clutch to drag or not release include heavy gear oil in the transmission that’s too thick for cold weather, defective or worn clutch pedal bushings or brackets, or flexing in the firewall or any release component attachment point.

For your understanding the meaning to some words used on the site

 

• Bell Housing: This is the cone shaped metal case that you can see when you underneath your car. If you have a front-wheel-drive car it’s stuck on the side of the engine under the hood. If your car is rear-wheel-drive, the transmission will be mounted underneath the car behind the engine.

• Fluid: Transmission fluid is very important

• Filter: All of that fluid has to be clean for your car to shift gears at the right time. To keep things fresh, your transmission has a filter to catch any dirt.

• Clutch

• Dual mass fly wheel

• Solid fly wheel

 

Advantages to having a manual transmission

• Manual transmissions are typically more efficient than automatic transmissions. This is because manuals generally involve a clutch instead of a torque converter, which can cause significant power losses. This results in both better acceleration and fuel economy.

• Manual transmissions normally do not require active cooling, because not much power is dissipated as heat through the transmission.

• The heat issue can be important in certain situations, like climbing long hills in hot weather, particularly if pulling a load. Unless the automatic’s torque converter is locked up (which typically only happens in an overdrive gear that would not be engaged when going up a hill) the transmission can overheat. A manual transmission’s clutch only generates heat when it slips, which doesn’t happen unless the driver is riding the clutch pedal.

• A driver has more direct control over the state of the transmission with a manual than an automatic.

• Manual transmissions generally require less maintenance than automatic transmissions.

• In addition, many people feel that driving a manual forces the driver to pay more attention to the road and to other cars, making it more difficult to become distracted.

• Cars with manual transmissions can be started when the battery is dead by pushing the car into motion (or allowing it to roll down a hill) and then engaging the clutch in third or second gear. Most automatic transmissions do not have this capability.

• Manual transmissions work regardless of the orientation angle of the car with respect to gravity. Automatic transmissions have a fluid reservoir (pan) at the bottom; if the car is tilted too much, the fluid pump can be starved, causing a failure in the hydraulics. This could matter in some extreme off-roading circumstances.