Clutch Noise

[endgame56]

OK, can anyone help me identify this noise:

https://www.youtube.com/watch?v=DVYB6pcE6IQ

I'm assuming throwout bearing despite the fact that most people say the TOB makes noise when the clutch is disengaged.

It goes away as soon as there's just a little pressure on the pedal. Clutch is still engaged at this point so I doubt it's the input shaft bearing on the transmission.

I should mention I put in a new Exedy clutch kit about 7k miles ago. This didn't just start, but it is a more recent development. If it is the TOB, aside from pulling the trans and replacing it, do I have any options to remedy this?

Honestly, if it involves pulling the trans I'll probably just wait until the noise starts drawing looks in traffic, or it just gives up and commits seppuku. Whichever comes first really.

 

[RonJR]

I couldn't hear the noise very well, but based on your description you have the classic Toyota "clutch chirp". Google it for more information. It has been a big problem on later model Tacoma's. The good news it is not harmful and you can run 10's of thousands of miles that way (my '94 is proof of that). The bad news is it may drive you crazy. There is nothing wrong with the TB itself, nor is anything about to fail.

The basic problem is a defective clutch installation, such that all of the clutch fingers on the throwout disc were not perfectly aligned. Because of this, as the throwout disc turns, it causes the throwout bearing to rock on the transmission output quill (the hollow fixed shaft that houses the rotating transmission input shaft). The rocking motion eventually causes the TB to start squeaking on the aluminium quill. When you lightly press the clutch pedal, you put pressure on the TB stopping the rocking motion and thus the noise.

The only permanent fix is to pull the transmission, align the clutch fingers to within .020" as per the FSM using a dial indicator, and then replace the TB and the hollow quill on the input of the transmission. On the 2nd gen, that quill is a replaceable part. On later Tacomas, it's cast into the transmission housing so requires replacing the transmission. Not sure about the 3rd gen 4runner.

You can get some relief by lengthening the clutch rod slightly to keep light pressure on the TB to stop the rocking. That won't hurt anything, but it keeps your master cylinder from refilling properly between clutch presses. If you have a good MC, it will work for quite a while. If your MC has a slow internal leak, you will lose pedal travel eventually.

You can also squirt some lithium grease up into the bell housing to lubricate the TB on the transmission quill. That will only stop it for a few hundred miles, however.

I've been living with it for 15,000 miles on my '94. No other problems except the noise.

 

[endgame56]

I couldn't hear the noise very well, but based on your description you have the classic Toyota "clutch chirp". Google it for more information. It has been a big problem on later model Tacoma's. The good news it is not harmful and you can run 10's of thousands of miles that way (my '94 is proof of that). The bad news is it may drive you crazy. There is nothing wrong with the TB itself, nor is anything about to fail.

The basic problem is a defective clutch installation, such that all of the clutch fingers on the throwout disc were not perfectly aligned. Because of this, as the throwout disc turns, it causes the throwout bearing to rock on the transmission output quill (the hollow fixed shaft that houses the rotating transmission input shaft). The rocking motion eventually causes the TB to start squeaking on the aluminium quill. When you lightly press the clutch pedal, you put pressure on the TB stopping the rocking motion and thus the noise.

The only permanent fix is to pull the transmission, align the clutch fingers to within .020" as per the FSM using a dial indicator, and then replace the TB and the hollow quill on the input of the transmission. On the 2nd gen, that quill is a replaceable part. On later Tacomas, it's cast into the transmission housing so requires replacing the transmission. Not sure about the 3rd gen 4runner.

You can get some relief by lengthening the clutch rod slightly to keep light pressure on the TB to stop the rocking. That won't hurt anything, but it keeps your master cylinder from refilling properly between clutch presses. If you have a good MC, it will work for quite a while. If your MC has a slow internal leak, you will lose pedal travel eventually.

You can also squirt some lithium grease up into the bell housing to lubricate the TB on the transmission quill. That will only stop it for a few hundred miles, however.

I've been living with it for 15,000 miles on my '94. No other problems except the noise.

Thank you for the detailed reply! After reading what you wrote here, and doing a little googling, I'm pretty sure that's exactly what is going on.

Lengthening the clutch rod won't cause any premature wear/damage to the TOB or fingers? If it won't hurt anything I'll probably go that route.

My MC is working just fine at the moment, but even if that means I have to rebuild it at a later date, that still sounds more enjoyable than dropping the trans again.

 

[RonJR]

I ran mine with the lengthened rod for about a year and a half and about 12,000 miles with no ill effects. Worked well. Eventually though I started getting flakey clutch operation so I abandoned that. I might rebuild the clutch hydraulics this summer and go from there. I've read about others who have run 20-30,000 miles that way, so I don't think it hurts anything. Even in normal operation, the TB is always contacting the clutch fingers and always spinning, so you haven't changed anything really. Just a slight bit more of pressure.