If the throw-out bearing is going bad, how much time do I have?
 

The truck has just developed a ringing/whining sound and haven't figured what it is exactly. It is intermittent when the engine is idling and worse in cold weather. I can't find any pulleys on the front of the engine that seem bad and the tensioner has been replaced very recently.

From reading many threads here, it sounds like it could be the throw out bearing. If it is, here's the question. Is it possible to estimate how long it will still function? I am about to go on a 1500 mile trip and there's not enough time to do the work before leaving. Will it last this much longer or is it likely to completely fail before I get back? Thanks in advance for any advice!

I don't know I would chance the trip with a bad throw out bearing. When mine went it came apart in three pieces with all the bearings in the bottom of the bell housing.
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Because the clutch system is hydraulic the throwout bearing is always in contact with the pressure plate fingers. If the throwout bearing is falling apart then it can affect clutch engagement. And you'll usually feel the rough feedback in the clutch pedal too if the TOB is the problem. The video below will help understand what I mean.

The pilot bearing can squeal but not all the time because the only time the pilot is spinning is when the input shaft and crank arent matched speed. And that happens when you're sitting at a stop light with the clutch pressed and the transmission in gear (really bad habit), and momentarily while you're shifting gears as the disc realigns with the speed of the crank.

But in saying all that, you should be able to tell if what you're hearing is coming from under the truck or if its coming from under the hood.

One common component that can make noise is the tensioner. If you suspect anything under the hood then get yourself a mechanics stethoscope, or a wooden dowel/stick/or long screwdriver, and search out the noise.

Not long when mine came apart it ruined the pressure plate as some of the bearings got between the throw out bearing case and the fingers on the pressure plate bending them

Thanks very much for all the comments and especially for the kick in the pants. I really needed it! I shouldn't have been considering a trip with a problem like this.

After more listening/investigating, the sound does seem to be coming from the clutch area. Also, when idling, pressing the clutch pedal makes the sound immediately go away.

The truck now has 196,000 miles and I'm going for the new clutch. Without power modifications, it sounds like (reading many threads here) my best option is the LUK 05179 kit (with new DMF and organic clutch material).

With my high mileage, is there anything else I should do at the same time? Order a new clutch fork also? Any of the hydraulic parts? Thanks again

I use southbend clutch in my truck they come as a complete kit, hydraulics clutch fork ect, while the tranmission is out I would go ahead and replace the rear main seal and change the fluid in the transmission I'd it hasn't been done before.

The LuK clutch is essentially stock equipment. The advantages to going with either Valair or South Bend is they usually have a larger sealed roller throwout bearing, and possibly more holding power depending on what model you choose. Either way, I'd suggest giving them a call and asking for their opinion. :thumbsup:

Check and have the flywheel resurfaced, no sense for new clutch on a used flywheel,probable has wavy surface.

Since I'm working against a fast-approaching deadline, I'm thinking I'll just get the clutch kit with a new flywheel (and watch the moths fly out of my wallet). I thought this would be better than trying to track down a machine shop I like that could work on such short notice. I agree the flywheel must have some waves in it - it's not a perfectly smooth takeoff anymore when starting from a stop when a trailer is hooked to the truck.

Also, from my reading here, I found some saying that the DMF can't be re-surfaced, then others saying it could. Which is correct?

As long as I'm asking questions again, how about supporting the engine before removing the transmission? My service manual says to to it but most write-ups here didn't include this step. Is it necessary?

If you believe the throwout bearing is the problem then you can simply pick one up at your local parts store, pull the transmission back just far enough to get the input shaft out of the clutch hub (about a foot), and then simply reach in and replace it. I know its not the ideal thing to do and will still require getting the transmission disconnected from every, but its cheaper than a full new clutch and depending on how well you treat your clutches with proper driving habits, it may last another 100k miles. Yes, the transmission will still have to be disconnected from everything but at least you wont have to drop it to the ground.

Contact southbend clutch tell them what you have and they will get the right clutch for your set up.
The DMF is junk you will have more gear rattle without it but your removing the weak link.
and you don't have to support the engine it will sit right were it is and not move. If your going to do this yourself you will need a good transmission jack and a freind I just shipped my clutch back to southbend to get it rebuilt and it weighed 118 lbs flywheel and all.
Check the rear main seal but it takes a special tool to get it set to the proper depth.

I installed the SB 1947 OK-HD. I used a floor jack under the front of the engine to use a little lift on the front to help the shift tower clear the floor pan. I used a semi trans jack which made the job really easy, as long as you have a good jack it will go pretty easy. My throwout bearing went at about 120,000, my clutch and pressure plate were in great shape, no hot spots or marks, and never slippped. If I had not already bought the SB clutch kit I would have just replaced the throwout bearing. The pictures are of my stock clutch and flywheel, the marks you see on the flywheel are finger prints.
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