View Thread: Clutch chatter


87 Supra Turbo
The last few days it's been pretty cold up here (-15c) and I've noticed that when my truck (B2200) is cold the clutch chatters when the revs get above about 3000. The clutch pedal is also quite stiff as if the clutch fluid has turned into molasses. Both of these problems go away after about 15 minutes of driving. I checked the clutch fluid and it isn't dirty and seems to have the correct consistancy. There are about 150K Kilometers on it and I'm pretty sure it's the original clutch.

Do you think that the clutch is on it's last legs?

Sia Bani
by the description, it definately sounds like you're going to be replacing it soon, but what do I know....I drive a slush, right?"

Devoid of WRX
Do you mean the clutch chatters while engaged???? Is it slipping?

A quick test to check for a slipping clutch:

When you truck is warm (including the clutch) start off in 1st gear, accelerate, and throw it into 5th gear. A good clutch will grab and cause the engine to lug. If the clutch is on its way out, your RPM's will soar and then drop back down as the clutch finally grabs.

Remember, during the shift from 1st to 5th, shift like you normally would - quickly. Don't feather out the clutch or you defeat the purpose.

911GT2
Very interesting test. What's to say the revs won't drop too low and stall out?

Sia Bani
Originally posted by 911GT2
Very interesting test. What's to say the revs won't drop too low and stall out?

I think he's saying that if your clutch is still good, the revs WILL drop low and stall out. However, if your clutch needs replacing, then it won't and it'll rev high!

911GT2
Ah, i see. But is stalling your car that good a gauge of clutch performance??

Sia Bani
Originally posted by 911GT2
Ah, i see. But is stalling your car that good a gauge of clutch performance??

it won't hurt, especially being in 5th.

Devoid of WRX
It's just a quick, easy test to determine how well your clutch is still holding.

Of course, if you like, you could drop your transmission and have a look at the thing.

3 seconds versus 3 hours? It's up to you!

As far as stalling goes, you don't have to let the car stall. You should be able to tell immediately whether or not the clutch is slipping, then you just clutch back in and don't stall. However, the few times and cars I've done this on, the car always managed to lug along in 5th gear without stalling. You won't hurt anything, so don't worry.

87 Supra Turbo
I'll give that a try tomorrow. Just as an aside if I do end up getting the clutch replaced what should I expect for clutch break in? I've never had to have a clutch replaced before so can you tell me what to expect in terms of break in, how the truck will drive when I get it back etc.?

Thanks.

911GT2
The break-in period for a clutch shouldn't be any more than 500 miles tops. Ask the guy about it, he'll probably just ask you to take it easy for about a week.

A-Tech
many cars have a little dust boot you can take off and just look at your whole clutch assembly, of course, you cant really see the face of the pressure plate.

Devoid of WRX
The new clutch shouldn't need much in the way of a break-in. Just treat it nicely for the first couple hundred kilometers, and you shouldn't have any problems. Ask if they plan on resurfacing your flywheel, or if it needs it at all.

87 Supra Turbo
Okay I went out earlier and tried your suggestion Devoid. When I shift into fifth the truck just starts to sputter, the revs don't go up at all. I suppose I'll take it to a transmission shop next week when I get some time and have it checked out.

If it's a replacement I suppose it would be around $500 or so right?

Devoid of WRX
Well, to tell you the truth, I'm confused. It sounds like your clutch is still ok. What exactly is this "chatter" you are refering to? What exactly happens when you hit 3000 RPM?

87 Supra Turbo
When it gets to around 3000 the truck starts to buck a bit. It's similar to shifting from first to fifth. It will also do it if I'm driving at a constant speed of say 70kph. Oddly it will not do this if I rid the clutch just a teeny tiny bit. It only does this when it's cold. After I've driven for about 10-20 minutes the problem is gone.

Devoid of WRX
Sounds to me like maybe you have more of a fuel delivery problem or something. Hmmm....

87 Supra Turbo
I suppose it could be fuel. But what about the stiff clutch when its very cold?

Devoid of WRX
Not sure about that. It's not like the fluid could actually be stiff. My guess would be that your throw-out bearing is getting worn, and once it heats up, it loosens up a bit. Again, that is my GUESS.

911GT2
WRX sounds right. Maybe your fuel delivery system (any part of it, impossible to tell without looking) is clogged and loosens up as the engine heats up.

A clutch isn't used very often so it doesn't get a chance to "heat up" as the rest of your engine does. A good shift hardly even causes friction, only what's necessary.

SLP Addict
Im not experienced with this type of thing, but 911 to my understanding is VERY knowelgable, so he's prolly right.

911GT2
Throwout bearings will outlast several clutches barring some kind of horrible alignment problem.

Sometimes fuel pumps/lines seize in the cold and can cause uneven gas distribution. Try letting your truck warm up for a couple minutes first on really cold mornings.

87 Supra Turbo
Well by some bizarre twist of fate the weather for the last week has been really warm so I'm not sure if I fixed it. I usually let it warm up for about 5 minutes or so if it's really cold but I still get the same problem.