zf6, Clutch out or glazed??

[Young-SC-Owner]

Hey guys, today i was driving along and in 5th gear (ovr drive) the clutch would slip but then come back down to normal RPM....example...i woul give it throttle, then rpms would raise about 300 rpms like it was slipping then would slowly come back down to the actual RPM for the speed i was going.... does that sound like a glazed clutch issue? or a clutch going out?

And is there a write up on a clutch replacment, or should i make one.

[forddieseldoctor]

That sounds like a slipping clutch to me. Sounds like a fairly bad one if it's slipping in 5th gear.

[Young-SC-Owner]

Well, i guess it would be "6th" it doesnt do it in any other gear, and oddly enough it didnt do it this evening when i was leaving the farm....I tried to recreate it but it wouldnt do it...hmmmm. Maybe oil in there? leaky slave? hell may pull it apart to see wtf is going on

[e99f2506sp]

Originally Posted by Young-SC-Owner

Hey guys, today i was driving along and in 5th gear (ovr drive) the clutch would slip but then come back down to normal RPM....example...i woul give it throttle, then rpms would raise about 300 rpms like it was slipping then would slowly come back down to the actual RPM for the speed i was going.... does that sound like a glazed clutch issue? or a clutch going out?

And is there a write up on a clutch replacment, or should i make one.

I had this exact same thing happen to me last week. Strange thing I was cruising along in od, gave it some gas going up a hill, the rpms went up like it was slipping, i slowed down and downshifted to 4th and tried to get it to do it and it wouldn't, so i shifted back to od and tried it again and it slipped again. I got to where I was going and tried to recreate it several times on the 150 mile trip home and counldn't. It hasn't done it since and I don't know what happened. I'm guessing it was just a warm clutch (after 150 miles there) showing the very early signs of slipping. I'm in no hurry to buy another one just yet since the clutch i want is almost a grand

Originally Posted by forddieseldoctor

That sounds like a slipping clutch to me. Sounds like a fairly bad one if it's slipping in 5th gear.

Actually an o/d will show the slipping before any other gear because the torque seen by the clutch from the wheels is greater in a high gear than in a lower gear. Low gears would reduce the torque seen by the clutch from the wheels. IE The torque is reduced by the gear ratio in the transmission.

[forddieseldoctor]

Most clutches that I've had slip will slip under high load and high rpms in a lower gear like going up an on ramp.

[e99f2506sp]

Originally Posted by forddieseldoctor

Most clutches that I've had slip will slip under high load and high rpms in a lower gear like going up an on ramp.

Thats true too, if you think about it though thats when the most torque is put to the clutch in the lower gears, when they are in the upper rpms.

If you notice with a clutch thats starting to slip, it will always start to slip a little lower in the rpm band range as you shift up through the gears.. It may not slip at all in 1st or 2nd, but say it slips at 3k in 3rd, then it will most likely slip at 2700 in 4th, and right at crusing rpm in od. It being an overdrive gear also puts a lot more torque on the clutch.

As the clutch starts to wear, you will notice it in lower gears. If its slipping in 1st or 2nd it will be pretty much useless in higher gears.

I know this sounds the exact opposite than what you'd expect to hear, I used to think the same way and it took me forever to realize the way it really happens. Everyone automatically thinks the most torque is being put through the clutch at really low rpms as you've got your foot to the floor but thats not the case.

[forddieseldoctor]

Like I said most. They can slip in all different places.

[e99f2506sp]

Yup, just generally show the first signs of weakness in overdrive gears and higher rpms in the other gears.