Intermittent slipping clutch SL-1

[steve seibel]

I've got a Saturn SL-1 with a very intermittent slipping clutch.

When it's slipping, the symptoms are as follows--

I can shift up or down through the gears no problem, and as long as I keep the acceleration gentle, there's no evidence of the clutch slipping--

But if I floor the accelerator, above say 2000 rpms, even if I'm just driving down the highway and it's been maybe more than 10 or 15 minutes since I last shifted-- the engine revs way up with no increase in speed.

Once I see this happen, it seems likely to happen again every time I floor the accelerator (again above say 2000 rpms) for the rest of the trip, but I don't know if that's because the clutch is getting hot and therefore more prone to slip, or if it's just because whatever intermittent condition is causing the problem is still persisting.

I don't think the root cause is simply the clutch getting hot through sloppy shifting, because I'm careful when I'm shifting to let the rpms fall back to an appropriate level before re-engaging the clutch, and because the problem will happen even long after the last shift.

The clutch was replaced only about 8000 miles ago. The reason I had it replaced is that I had a (very similar, maybe the same) intermittent slipping problem, originally *extremely* intermittent (happened once and then not a again for many months), that suddenly got a whole lot more persistent so that I could replicate it at will. That clutch had well over 100,000 miles on it. Mechanic said he could see it was very worn.

Well, now I'm thinking maybe it needed replacing, maybe it didn't, but anyway, for sure I have an intermittent problem now.

A couple weeks ago I had the very frustrating experiencing the slipping, being able to replicate it persistently, then taking the car to the mechanic who did the work, taking him for a drive-- and I could no longer replicate the slipping. Argh! Even tried accelerating hard while braking at same time and couldn't make it slip. Mechanic took the car and looked at it and said didn't see any evidence of material being shed from from the clutch disk, or oil on the clutch disl.

The clutch master cylinder is appropriately full of fluid.

Back in September I posted about another problem where the clutch wasn't fully disengaging (fluid in master cylinder had gotten low) but that seems to have been fixed by filling the master cylinder back up, and pumping the clutch pedal a *lot* to work out bubbles. (See my thread http://www.saturnfans.com/forums/sho...d.php?t=272851 ) I did the "wire test" and got numbers that seemed reasonable -- just a tiny bit low -- see post #20 in thread noted above-- but this should encourage the clutch to fail to disengage, not to fail to stay engaged. And it seems to have no problem disengaging now. It seems to me that this problem was probably unrelated to my current one-- but maybe I'm missing something.

Thanks for any help that may be offered!

[steve seibel]

Originally Posted by steve seibel

I've got a Saturn SL-1 with a very intermittent slipping clutch.

(1997 Saturn SL-1)

[billr]

It's not the heat of slipping once at the beginning of a trip.

What make and P/N clutch did you put in? I assume the disk, pressure-plate, and throw-out bearing were all in a kit.

I didn't look yet for the wire-test in the old thread, but I don't think you can dismiss a marginal wire-test. These clutches are self-adjusting, so I think a short throw could mean the clutch is dis-engaging fully, but not engaging fully. Opposite of the other possibility you are counting on.

[steve seibel]

Originally Posted by billr

It's not the heat of slipping once at the beginning of a trip.

What make and P/N clutch did you put in? I assume the disk, pressure-plate, and throw-out bearing were all in a kit.

I didn't look yet for the wire-test in the old thread, but I don't think you can dismiss a marginal wire-test. These clutches are self-adjusting, so I think a short throw could mean the clutch is dis-engaging fully, but not engaging fully. Opposite of the other possibility you are counting on.

Thanks-- I'll try to get that info and post it--

Generally speaking, is it safe to say that problems with the master cylinder and slave cylinder can cause problems with clutch fully disengaging, but not problems with clutch staying engaged? Or is there a way an oddball problem with one of these could cause the clutch to slip (not stay fully engaged) with the clutch pedal is simply being left alone (all the way up)?

[billr]

I'll have to think about how to describe it, and post later as I am out of time.

However, I do not think it is safe to say the hydraulics will only, or even more commonly, cause problems with dis-engagement.

[trottida]

Could it be the rear main seal or quill bearing seal is leaking and contaminating the friction disk?

[billr]

Maybe the quill. Any oil from the rear main gets slung of by the flywheel, never makes it "around the corner" to the clutch. Assuming, of course, the rear main leak isn't so bad that the bell-housing starts filling with oil...

[93twincam]

If the clutch disk and pressure plate are relatively new and are the correct PN's and are not damaged, and you have confirmed there is not oil on the clutch from a rear main leak or quill seal leak, I would suspect the hydraulic system.

There may be debris in the system intermittently clogging the line(s) and/or a port, acting like a one way check valve when stuck in the right spot. The debris can work it's way around the system which could explain the intermittent nature of the issue. If there is debris acting as a one way check valve in the system, then theoretically depending on the direction of flow the debris is blocking, it could result in clutch staying applied when depressing the clutch pedal, or preventing complete clutch engagement when the clutch pedal is fully released. Think of it similar to how brake calipers can be stuck applied when the flexible rubber lines begin to deteriorate and swell, blocking the fluid from flowing out of the caliper when the brake pedal is released.