HOW TO EXTEND THE LIFE OF YOUR 4WD'S CLUTCH
Nothing will grind an off-road adventure to a halt faster than a failed clutch, even in a newer 4WD. nowadays, modern clutches are designed to increase driver comfort, which is great for your left leg. But does it come at the cost of longevity?
Your 4WD's clutch plays an important role in the overall performance, comfort and drivability of your manual 4WD. On top of that, it can also be an expensive and time-consuming job to repair if it were to fail prematurely. So, with that in mind, here are our tips to doubling the life of your 4WD's clutch.
HOW A CLUTCH WORKS
The clutch in a manual gearbox has two very important jobs to do. It disconnects drive from the engine so you can change gears easily or slow to a stop, and it helps to dampen some of the shock loads placed on the drivetrain as you take off or slow down.
Clutches haven't changed much over the years. You push the pedal - the pedal forces hydraulic fluid from the master cylinder to the slave cylinder. The slave pushes on the clutch fork, which levers the throw out bearing to de-activate the clutch. Inside the bell housing, the clutch itself is made up of a friction plate, a pressure plate and a thrust (or throw out) bearing.
When your foot is off the clutch - in its resting position - the friction plate is sandwiched under pressure between the pressure plate and the engine’s flywheel by the diaphragm spring, which transmits drive to the gearbox via the input shaft.
As you push on the clutch pedal, the thrust bearing is pushed against the diaphragm spring of the pressure plate, releasing the clamping force and allowing the friction plate and gearbox to turn independently of the engine.
COMMON CAUSES OF 4WD CLUTCH FAILURE
Driving style, heat and oil contamination are the most common causes of clutch failure. Engine power ups that push more power through the driveline. Fitting larger wheels and tyres. A lot of towing of heavy loads. And oil leaks or ingress of other contaminants like mud or water all drastically shorten the life of your clutch.
EARLY WARNING SIGNS YOUR CLUTCH IS WEARING OUT
One of the first signs of a worn clutch is a burning smell when driving under load up a hill, or when you first take off from a set of lights. If it worn enough, the engine revs will rise but the road speed will stay the same or feel like it’s in neutral even with the clutch fully disengaged. In some cases, you made also experience a shudder when engaging or disengaging the clutch. All of these are early warning signs that your clutch needs attention.
WHAT ARE HEAVY DUTY CLUTCHES?
While standard clutches are do the job and are great for comfort - heavy duty or performance clutches are usually beefed up in a few key areas. Heavy-duty clutches will provide increased clamping force which helps to reduce the chances of slipping in extreme conditions or when the vehicle has extensive modifications. The friction plate and friction material are all harder wearing and provide increased friction capabilities. The dampening springs may be firmer. And the bushes, rivets and fasteners are heavier duty, which reduces the chances of failure when driven under extreme conditions.
5 WAY TO DOUBLE THE LIFE OF YOUR CLUTCH
Your clutch is no different to any other serviceable part. Go easy on it and it'll last years longer.
Avoid using the clutch when drive through bog holes and water crossings
Replace leaking remain oil seals or gearbox seals
Keep engine RPM to a minimum when engaging and disengaging the clutch
Ensure clutch pedal free play is within factory specs
Drive in 4th gear when towing at highway speeds to reduce the load on the clutch
HOW TO TEST THE CONDITION OF YOUR CLUTCH
Firstly, test the clutch pedal feel - it should operate smoothly and engage midway through the pedal's range of movement.
Another option is to try to take off in 4th gear – being extremely careful of course. If it stalls the clutch is doing its job, but if you can drive off, the clutch is slipping too much and will need to be replaced before long.
You can also change up into a high gear at a slow road speed to load it up and if it begins to slip there’s a good chance it's time for a new clutch.