Truck Question

[41magsnub]

So..  my truck makes a rattling noise when it drives.  If I push in the clutch even a fraction of an inch (truck still in gear and driving fine) the noise goes away.

I'm thinking throw out bearing..  thoughts?  Insults?  Other ideas?

Truck is a 1995 GMC S1500 4x4 with a V6.

[never_retreat]

How many miles?

[41magsnub]

88K

[sanglant]

slack in the clutch line?(cable )

[Jim147]

I can't picture that one. Been away from anything but my own stuff for a while. Does that, or maybe did it, have a rubber boot for the clutch fork where it comes out of the bellhousing?

jim

[sanglant]

way in left field, but could the actual clutch pedal be loose? if so pushing up(or to the side) on the pedal would stop the rattle.

[41magsnub]

More detail, I cannot hear it in the cab at all with the windows closed so it has to be coming from underneath the somewhere.  Where I notice it is when I drive down a road with houses or fences that reflect the noise back at me.  Then it is very loud.

[Tallpine]

I would guess somewhere in the clutch linkage. 

Under normal driving conditions all of the clutch parts are relaxed - well, except for the pressure plate springs that hold everything together.  If you had problems in there I would expect a noise relevant to speed, not a "rattle".

You're just going to have to crawl under it look things over (or under ).  Might help to have somebody inside push the clutch so you can watch what is happening.

[Brad Johnson]

If it goes away when you put pressure on the clutch, chances are it's the throwout bearing.  Luckily, most are easy to change.  4x4 is a little bigger pain because of the extra driveshaft and transfer case, but not terribly so.

With your mileage might as well replace the clutch and have the flywheel surfaced while you have the tranny off.  Cheap(ish) insurance.

Brad

[Tallpine]

If it goes away when you put pressure on the clutch, chances are it's the throwout bearing.

I've always found that that a bad TO bearing makes noise when you press the clutch pedal 

[Brad Johnson]

Can work either way.  Best to check everything by manipulating the clutch arm by hand, or in the case of a hydraulic clutch getting someone to engage the clutch while watching things from underneath.

If you're lucky your setup will have an inspection plate you can remove to you can see the throwout bearing fork (or slave assembly if it's hydraulic).  Nothing like grabbing parts and giving them a good yank to see what is an isn't loose.

Brad

[CNYCacher]

Bad noise when pressing the clutch pedal that goes away when you release the clutch pedal is the throwout bearing.

Bad noise that happens while driving which goes away when when the clutch is fully depressed and gearbox in neutral, but comes back again if idling in neutral with clutch pedal released is input shaft bearing.

Bad noise that happens when driving, goes away when the clutch pedal is slightly depressed, but clutch is still engaged, is probably the throwout bearing, and it's failure is probably caused by mal-adjusted clutch linkage, since the TOB should not be in contact with the clutch plate fingers if you are not pushing the clutch pedal, and it obviously is if it's making noise going down the road.