I noticed a squeal when pulling off under load a few months ago. By pull off under load, I mean like pulling off quickly, rather than just a leisurely pace, or when carrying some cargo. Lately it has gotten worse, and has come to the point that it does it almost every time I start out. Truck has almost 11k miles, I've had several MT vehicles and have never killed a clutch prematurely, so it isn't me.
Anyway, to the point, my uncle is a Toyota tech, he listened to it, he says it's the throwout bearing. They'll apparently cover it under warranty (since the throwout bearing isn't a wear item in the sense that the clutch plate is a wear item - the only reason for one to go bad after this short a time is a defective part) and replace the entire clutch assembly (pressure plate, friction plate, throwout and pilot bearings.)
So really this is more of an information post than a question, just thought I'd share. Hopefully it will be fixed soon. If any of you have noticed an odd squeal as you're about halfway out on the clutch pedal, get it checked out. And if you need to replicate it for the tech, start off abruptly in 2nd instead of 1st and it'll do it a hell of a lot louder.
Here's one I believe to be related, he's just hearing it wrong (I though mine was coming from the rear at first, too - plus uncle asked me if it did it more on cold mornings, because TO bearings tend to.) http://www.toyotanation.com/forum/t122642.html
hmm that's intersting. i don't think it's the TO bearing though. the TO bearing will engage the PP whenever the clutch pedal is depressed, no matter what gear and no matter if the clutch disc itself is slipping. if it's the TO bearing you should be able to replicate the noise by simply pressing in the clutch pedal (engaging it with the PP and making it spin). or if it's an RPM related thing, by leaving the transmission in neutral, reving the engine like normal (as if it were in gear) and letting out the clutch. TO bearings also tend to make more noise when the pedal is fully depressed (bearing fully engaged with the most thrust load), not just when letting out the clutch.
your description sounds alot like a problem with the clutch disc itself, since it only seems to happen with a speedmismatch across the clutch (ie when it's slipping) which the TO bearing is insensitive to. this particularly true since you say it gets worse when you start from 2nd. hopefully your dealership will also think it's the TO bearing and you'll get your clutch fixed for free.
hmm that's intersting. i don't think it's the TO bearing though. the TO bearing will engage the PP whenever the clutch pedal is depressed, no matter what gear and no matter if the clutch disc itself is slipping. if it's the TO bearing you should be able to replicate the noise by simply pressing in the clutch pedal (engaging it with the PP and making it spin). or if it's an RPM related thing, by leaving the transmission in neutral, reving the engine like normal (as if it were in gear) and letting out the clutch. TO bearings also tend to make more noise when the pedal is fully depressed (bearing fully engaged with the most thrust load), not just when letting out the clutch.
your description sounds alot like a problem with the clutch disc itself, since it only seems to happen with a speedmismatch across the clutch (ie when it's slipping) which the TO bearing is insensitive to. this particularly true since you say it gets worse when you start from 2nd. hopefully your dealership will also think it's the TO bearing and you'll get your clutch fixed for free.
That was precisely my argument against it when talking to him about it - but he says as I'm releasing the clutch, while the TO is still on the PP fingers but the force with which it is pushing them is reduced, that's the point at which it's slipping on the fingers and squealing. Starting in 2nd doing it worse because the speed differential is greater. Got me Honestly, I believe it because he says it, and I know he's a very good tech and a very smart guy - but like you say, we'll see. My initial feeling was that it was the actual friction disc squealing as it slipped, basically like a brake pad can do on a rotor. But the holding power hasn't degraded, even though the squeak has gotten louder and more frequent, so maybe he's right. It'll be okay regardless, he said it's obviously from the clutch area, and they'd just throw in a complete kit no matter which component is dead. Basically he's going to take it to his dealer, and he has already diagnosed it, so it will be fixed under powertrain warranty even if he's mistaken.
Either way I'm sure it's just a fluke in regards to Tacoma quality, as I'm very good on clutches - the earliest I've ever had to replace one was at 130k miles, and that was on a 4-cyl 4Runner with 35" tires and stock gears (meaning I had little choice but to abuse the clutch.) Most of my vehicles I've never had to replace them, even in the 200k mile range. The fact that I found nothing similar searching here or another board leads me to believe I just got the lucky truck with either a defective part or a greasy fingerprint on the clutch disc or something.
I have 70,000 miles on mine and I have similar squealing (rpm based) noise when the clutch pedal is fully released, but as soon as the pedal is depressed just an inch, all is quiet. I have a new Release bearing (throw-out), clutch disk and pressure plate and that did not correct the issue. My old parts were considered like new which should have been a red flag at the time that something else was wrong. The old Pressure Plate fingers do show signs of scrapes and wear and the Release bearing shows fresh bright metal where it contacts the fingers, although everyone overlooked this until I sat down one day and researched Toyota manual transmission TSB's and inspected my old parts. I always ask for the old parts on any repair.
The TSB I found on previous generation Tacoma's led us to suspect the slave cylinder, which is being replaced tomorrow. I have had several shops listen to it and even the dealer thought it was the Release bearing. The noise was originally temperature related and has appeared and disappeared with changes in temperature, although it seems like a permanent issue now that temps in my area are 30’s to 60s.
The first theory is that the slave is not applying enough preload to the Release Bearing against the pressure plate fingers and the Release Bearing is slipping or catching against the fingers. This assumes the Release Bearing is meant to stay pushed against the fingers with slight preload from the slave cylinder.
The second theory is the slave is not pulling the Release bearing far enough away from the fingers when the clutch pedal is fully released and at rest. This assumes that the Release Bearing is supposed to separate from the Pressure Plate fingers completely.
If someone knows for certain how the Release Bearing is positioned against the fingers when the pedal is not pushed down, that could help me figure this out.
The TSB for older Tacoma's referencing the slave also references the pilot bearing but on a 6 speed, there is no pilot bearing.
The other remaining possibility is that the Release bearing rides on an aluminum shaft that is press-fit into the Bell Housing (5 speeds and pre 2005 Tacomas are not press fit, but bolt on replaceable with an alignment tool, as it should be). This is a real bummer because if it is the shaft, the only repair option is a $620 bell housing and a full drain, assembly and rebuild of the tranny. I physically felt the low spots and wear spots on this shaft after the second tear down of my tranny but there are no signs of metal to metal scraping inside the Release Bearing and anywhere on the shaft. It just looked like the aluminum shaft was worn by a steel Release Bearing, not the source of a rotational squeal.
That sucks. Yours really does sound like the TO bearing, or something related. I hate when a problem sounds like something, but then replacing it doesn't fix it. Hopefully that slave cylinder will fix it for you.
We ran the truck on the lift and removed a small cover that allows us to see the pressure plate and release bearing in action (no need to drop out the tranny to inspect this.) There is definately a wobble on both the pressure plate and the release bearing, when the clutch pedal is released and at rest. The retainer bearing and pressure plate are spinning at all times and the retainer bearing maintains contact with the fingers on the pressure plate at all times. They spin together in sync. We applied pressure with a finger to the fork to stabilize the wobble of the release bearing, and that reduced the wobble and eliminated the squeal. The wobble must be causing the 2 components to loose contact or slip or grind while spinning in sync.
The bad news is that the press fit aluminum shaft, aka retainer bearing in most other manual trannys, that the release bearing moves forward and back along, is worn and causing the loose fit of the retainer bearing and subsequent wobble and squealing. That shaft can only be replaced with a new bell housing and full tranny rebuild, as far as we know. The dealer agreed to look at it again, make a diagnosis and report back to their Toyota rep. I'm at 2 years but double the mileage.
Has anyone else expereinced similar issues and had clutch parts replaced?
We ran the truck on the lift and removed a small cover that allows us to see the pressure plate and release bearing in action (no need to drop out the tranny to inspect this.) There is definately a wobble on both the pressure plate and the release bearing, when the clutch pedal is released and at rest. The retainer bearing and pressure plate are spinning at all times and the retainer bearing maintains contact with the fingers on the pressure plate at all times. They spin together in sync. We applied pressure with a finger to the fork to stabilize the wobble of the release bearing, and that reduced the wobble and eliminated the squeal. The wobble must be causing the 2 components to loose contact or slip or grind while spinning in sync.
The bad news is that the press fit aluminum shaft, aka retainer bearing in most other manual trannys, that the release bearing moves forward and back along, is worn and causing the loose fit of the retainer bearing and subsequent wobble and squealing. That shaft can only be replaced with a new bell housing and full tranny rebuild, as far as we know. The dealer agreed to look at it again, make a diagnosis and report back to their Toyota rep. I'm at 2 years but double the mileage.
Has anyone else expereinced similar issues and had clutch parts replaced?
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Honestly, I believe it because he says it, and I know he's a very good tech and a very smart guy - but like you say, we'll see. My initial feeling was that it was the actual friction disc squealing as it slipped, basically like a brake pad can do on a rotor. But the holding power hasn't degraded, even though the squeak has gotten louder and more frequent, so maybe he's right. It'll be okay regardless, he said it's obviously from the clutch area, and they'd just throw in a complete kit no matter which component is dead. Basically he's going to take it to his dealer, and he has already diagnosed it, so it will be fixed under powertrain warranty even if he's mistaken.
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