How to test if my clutch is going/slipping


#1

Hello i own a mazda 3 6 speed and im curious as how to test my clutch for slippage. I read on a old forum that to put the e brake up and put the car in 1st gear and release the clutch. When i did that my car tried to move but after a couple seconds i put it back in neutral. Another forum said to do the same but put it in 3rd as i released the clutch it stalled right away. Thoughts?


#2

In my experience a clutch that is starting to slip will slip much more readily in high gear than it will in a lower gear .


#3

I agree with Sloepoke… When a clutch begins to fail due to loss of friction material on the disc…you will see and hear the engine rpm’s rise when under load. For example you will be in 4th gear going up a hill and apply more power…the rpm’s will begin to rise without forward motion…its actually very obvious when it happens.

The other way clutches fail is when the rear main seal blows out and begins to coat the flywheel with motor oil…this produces plenty of slippage. Another way is when the springs in the pressure plate Fatigue…when they fatigue the clutch will feel basically “Lame” it will be soft and vague pushing it down…and it will not return with spring force back to the pedal being fully released. When you install a new clutch the difference in pedal feel is quite dramatic actually…this is due to healthy and new springs in the pressure plate. Another characteristic of the springs getting tired is that when you push the clutch pedal all the way to the floor…the clutch does not DIS engage entirely…this makes for difficulty putting the trans in 1st gear or any other really…this is because the springs are so tired and bent that they don’t allow full clutch disengagement. Happens all the time…I had to replace my Ford Exploder clutch for this reason alone…it has a good amount of friction material left on the clutch disc also…but there was no way to continue to use it…the pressure plate just gave up… Most commonly this happens to manual trans vehicles because the driver…doesn’t know how to operate a manual trans…they will come to a light and sit there with the clutch to the floor the entire time holding it disengaged…This is massively WRONG…do not do this. Just pop into neutral and wait…then select your gear and off you go

But getting back to a slipping clutch? You will feel it slip in the higher gears…under load…it will slip and you will feel it…

Blackbird


#4

The standard test for a slipping clutch is to place the front bumper against an immoveable object, like a tree; put the emergency brake on tight; put the transmission in its highest gear; and rev the engine while releasing the clutch as if you are starting off. If the engine continues to run after the clutch pedal is fully up, the clutch is slipping. If the engine stops with a “boomp”, the clutch is frictionally healthy.

If you can find it, look up “Clutch Burnout” on Youtube. A the owner of a ZO6 Corvette is trying to “roast off the rear tires”. The engine is reving; smoke is coming out all over; but the rear tires are not turning.


#5

@researcher That may have been advice for 1950’s vehicles that had massive chrome bumpers but with todays pricey bumper covers that is just wrong.


#6

@VOLVO V70 I agee that the “standard test” no longer applies. When I do a clutch test, I find an open path; apply the emergency brake; use right foot heel and toe to apply the service brake and rev the engine while releasing the clutch pedal. Again if the engine stops immediately with the clutch pedal fully up, the clutch is judged to be frictionally healthy.