Clutch Noise?

[markqc]

96 C1500 4.3L 5 Spd Manual
I noticed a little noise possibly from the clutch when starting off (either in First or Second Gear) Sounds almost like some "sheet metal cover" vibrating (Sorry, that's the best I can describe the noise) Could be something loose. It's too cold out right now to take a close look. Anyone seen or heard this before?

Thanks,

Mark

[shell1990]

How many miles are on the clutch?

[acewelderman]

Maybe a throw out bearing .Does the noise chang when you push the pedal in & out or hold it down?

[markqc]

The mileage is at approx 177Km (original) and the noise only occurs when I start off moving. I don't notice the noise when I push the clutch in or let it out when not moving so I think it is related to vibration at a certain engine RPM. I noticed if I start out with a higher RPM like over 1500 I don't seem to hear the noise. I think it may be something possibly the exhaust vibrating a little due to cold outside temps . It has been fairly cold the last week with night temps around -15 to -25 C and daytime around -10 to -15 C . Maybe some ice in or on the exhaust pipe. The clutch and transmission otherwise seems to operate as usual.

Thanks for your replies.
Mark

[markqc]

After studying it for a few days, it seems to make the noise around 1500 to 1700 RPM during acceleration. It seems to be more under normal acceleration or in other words when the engine has some "load" on it. Below or above this engine speed it doesn't seem to make the noise or if I am under harder acceleration/load. I do not hear the noise when I push the clutch pedal down, hold it down or let it out. Only when under engine "load" Would the throw out bearing make noise regardless of engine speed or load? This is a commuter vehicle and seldom carries a load. (Mileage is around 173 km) How long should the components last on a truck that is not used as a work vehicle. Most of my driving is at highway speeds.

Thanks,

Mark

[markqc]

It sounds like a bearing making noise. It will happen at low RPM like under 1000 when first taking off and at between 1500 and 1700. other than these conditions there is no noise. What is involved in replacing the throw out bearing? I would assume this is not a dyi job. Is this the same as the "input shaft bearing"? Any idea of cost of parts/labor for this type of repair?

Thanks
Mark

[shell1990]

the throughout bearing is on the front of the tranny and inside the bell housing, its easy to replace but if the clutch is bad you might as well put an new one on. If you want someone else to do it, it will cost from 500-700 dollars for the clutch and bearing.

[clampjockey]

your likely right when you say its the "input shaft" bearing. i had a dodge one time w/a 4spd, and the bearing/shaft made a terrible racket in all but 4th. i never changed it and it never blew apart. they can last a long time if your willing to put up with the noise.

[Cadillakin'98]

honestly markqc, I think it might be a simple rattling noise you hear. Something like a heat shield or a loose mount for the exhaust, possibly the rubber "donut". Based on the mechanical knowledge I do have, it would make since to me that a throw out bearing would make a noise regardless of RPM's and/or engine load but either less/more noticable at certain conditions. I have an automatic tranny in my '98 4.3L and in the mornings I hear a steady metal-to-metal vibration noise. But once at operating temp, I don't notice it as much, sometimes not at all (think I might have blocked it out). Als, once its warmed up, and I put it in gear I do know the noise goes away. I do know one of the metal straps holding my exhaust has broken at the weld and have been meaning to fix it for like the past year, but just somehow keep putting it off. Your best bet is to pull it into a garage somewhere (or out of the cold) and crawl under and take a look. It's alot cheaper, and less time comsuming, to deal with the coldness and take a look around underneath than it is to either replace the throwout bearing or pay someone else to do it, right?

[markqc]

Thanks for your replies. The noise does not seem to go away when warmed up. My first thought was something rattling like a cover of some type. What damage can be done if the bearing is not replaced right away while investigating the problem?

Thanks,

Mark

[Cadillakin'98]

Not really much of a mechanic, escpecially when it comes to transmissions, but I believe that the worst case scenario would be you just can't go no where no more. I believe that if the throw out bearing gives out completely, then you simply won't be able to engage the clutch. So you might even posibaly get it stuck in a gear. However, like any other mechanical problem, you should address the issue ASAP. If I'm wrong about the throw out bearing, somebody please correct me.

[SigGMC96]

Zip tie some peices of vacuum hose, or something similar in the gap of your rear spring packs. I had a noise like what you described which I thought was transmission related, however this fixed it *shrug* might work for you, if not.. it doesnt cost anything.

[markqc]

If the throw out bearing is going, would it not make noise whether it is in gear or neutral, or at all engine speeds? Or will this happen eventually?

Thanks

Mark

[rpreston]

I doubt its a throw out bearing. They usually only make noise when you push in the clutch pedal. Engine speed should not make a difference. The bearing is either engaged (with the clutch pedal pushed in) or disengaged (clutch pedal out). The bearing sets in the yoke and presses in on the pressure plate "fingers" releasing the clutch when you depress the pedal. When it's disengaged it doesn't even spin. That's why most of the time they only make noise when you push in the clutch pedal.
It COULD be the pressure plate making the noise. When they're going bad, sometimes the springs will rattle. The noise is at the opposite of a bad throw out. They'll make the noise when the clutch is engaged (pedal out). Engine RPM can make a difference then.
If it turns out that it is clutch related, It's really not a hard job to do yourself. Especially on a 2 w drive. You can get a complete clutch kit at most parts store for about 150 bucks. Thats everything, clutch, pressure plate, throwout bearing and pilot bushing. They even come with a plastic clutch alignment tool. If you and a buddy have a garage and tools, should take about 2-3 hours. I wouldn't try to do it alone unless you have a transmission jack.