Transmission/clutch issue

[pb2k]

I went to start my Yaris yesterday and immediately on startup I heard an odd noise/vibration. Similar thing when I popped it into reverse. I shut it off and popped the hood and for a moment I detected a burnt smell, but it quickly faded. I started it again this morning and there's a pronounced vibration in neutral, regardless of clutch position. I drove it in a quick circle and it still drive-able, but lots of vibrations when driving and shifting.

I'm not sure how all the pieces of the drive train fit together, but the only thing I can think of is that something on the engine side of the clutch has physically broken and is no longer balanced (not to mention debris floating around).

Has anyone experienced anything similar or have any other ideas as to what the problem might be? I'm in Nevada right now and was suppose to be headed back to Canada today, but I'm not sure I'd make it 5 miles, let alone 1200.

Car is 07 Hatch, 108,000 km (67k miles), transmission oil was just changed 8 months ago.

[CoryM]

If you don't see anything obvious externally, I would guess that your clutch disc has broken apart. If it's clutch material burning, it will be a very acrid smell.

[pb2k]

Originally Posted by CoryM

If you don't see anything obvious externally, I would guess that your clutch disc has broken apart. If it's clutch material burning, it will be a very acrid smell.

Yeah, the smell was bad, although it dissipated quickly and I didn't notice it when I started it up this morning. Maybe a piece of the wear material sheared off and is intermittently rubbing against the fly wheel, and the rest of the vibration is just due to imbalance.

[pb2k]

Took it to the corner mechanic, who said the clutch was fine, but the motor mounts were bad. $600 later and it vibrates worse than ever. Not sure If I should cut my losses and have it towed to a Toyota dealership, or let the guy have another go at it tomorrow.

[CoryM]

It's hard for me to advise w/o seeing the car. I would guess that you would do better elsewhere than the current mechanic, and the dealer would probably get the job done fastest (actual work time) if time is a concern. Yaris clutches last so long that aftermarket guys won't know how to do the job as quickly as the dealer guys. I've been a mechanic for a long time and have only done one Yaris/Echo clutch (my own!).

I would guess you have the right idea that a piece of the clutch disc came off. Unusual for a Yaris, but possible.

[pb2k]

It could be something else too i suppose. The mechanic mentioned something about a clutch inspection plate, and said it looked fine and nothing loose came out. Not sure if that's BS or not (I thought the clutch disc was nested in the transmission?).

If there's one thing I'm good at, its troubleshooting, so I'm gonna sit down with the guy today and work through it logically with him. The vibration is (now) so massive that we should be able to narrow it down (it has to be a major moving part).

[tmontague]

There is a plastic plate that allows you to pear into the area where the clutch sits. It's useful to look for a main seal leak. That is likely what he looked into and saw no loose pieces.

[CoryM]

As mentioned, you can see into the bellhousing by looking through a cover, and the clutch-fork-boot. You can't see the actual disc very well though.

Does it vibrate any time the engine is running? At idle in neutral? Clutch pedal change the vibration at all?

[pb2k]

Vibrates all the time now. It started out as a shudder when I started the car, was intermittent in neutral regardless of clutch position, vibrated when shifting, and was intermittent and less pronounced when in gear and driving (I never took it over 1800rpm/20kph, but I suspect the mechanic did).

I started the car at the mechanic last night and the vibration was constant and 3x more pronounced than it had ever been. I didn't try to drive it, just shut it off, so I don't know the current state of vibration while driving.

He's going to do a more detailed inspection today/tomorrow, but if he can't find anything, he wants me to come pick it up and drive it over the weekend, just to see if it throws a code. Seems a bit dodgy to me; could just as easily destroy the engine.

[dogsridewith]

Can a "miss" on one or two cylinders do this? (wouldn't think so...and wouldn't make that smell...unless maybe unburnt fuel burning debris off the exhaust system) Pull plug wires while running to find miss...also rod knocks? Failing head gaskets cause a miss due to coolant in the combustion chamber(s).

[tmontague]

Originally Posted by pb2k

Vibrates all the time now. It started out as a shudder when I started the car, was intermittent in neutral regardless of clutch position, vibrated when shifting, and was intermittent and less pronounced when in gear and driving (I never took it over 1800rpm/20kph, but I suspect the mechanic did).

I started the car at the mechanic last night and the vibration was constant and 3x more pronounced than it had ever been. I didn't try to drive it, just shut it off, so I don't know the current state of vibration while driving.

He's going to do a more detailed inspection today/tomorrow, but if he can't find anything, he wants me to come pick it up and drive it over the weekend, just to see if it throws a code. Seems a bit dodgy to me; could just as easily destroy the engine.

There is the potential the do more damage, but likely it is strictly the transmission that has the issue. Problem is the only way to check is to separate the trans from the engine and that costs $ that most people don't want to spend just to get a diagnosis. This is likely why your mechanic isn't just tearing things apart to give a proper diagnosis.

[pb2k]

The mechanic spent some more time on it today, but couldn't come up with anything, so he had me come pick it up. He thinks the motor mounts are just stiff and need to be worn in. I don't really buy that explanation, so I think I'm gonna have to risk driving it the 45 miles to the nearest dealership and see if they can give me a better answer.

It's not bad at warm idle (600 rpm), but the whole passenger side (suggests it's not the transmission) starts to shake around 900 rpm and the plastic interior starts chattering over 1300 rpm and then subsides around 3000 rpm, which I assume just means less of the vibration results in audible noise at that frequency.

The odd bit is that placing your hand on the engine cover while revving doesn't feel all that bad.

[CoryM]

Time to leave that mechanic and try elsewhere.

The only reason I suggested clutch is because you mentioned the smell. Burnt clutch is a very acrid smell that almost burns your nose and takes a while to dissipate. I would suggest ruling out a misfire first in case the smell you noticed was just rat piss on the exhaust (right after it chewed your wires) or similar. If it it shaking at idle all you need is a 10mm socket to remove the engine cover. With the vehicle idling, unplug one ign coil connector and it should run much worse. Plug it back in and then do the next one. If you find one that does not change how rough the engine runs, you have a misfire, and that is the cylinder that is misfiring. Remove that coil, and swap it into another cylinder and see if the misfire follows it.

You're looking for something like this but just disconnect the connectors:

https://youtu.be/imUSBswABJo

[pb2k]

He said he tested the ignition system, dispite that kind of error nearly always throwing a code. The car also doesn't seem to be having trouble making power.

[pb2k]

Took it out on the interstate today and did a few laps between the exits. As I noted earlier, it's not bad above 3000rpm, so I've deemed it stable enough to take it into St. George on Monday.

If it is something deep inside the engine, then I'm gonna have a tough decision to make. If the estimate is >$1000 (plus the $600 already spent), I think I'm gonna go for broke and try to get it home. My parents will be away, so I can commandeer their garage and try my hand at tearing down an engine (I suspect putting it back together again will be the hard part). Worst case scenario, I'll be selling used car parts on ebay for the next 2 years

Thanks to everyone who replied; I'll update with results on Monday (assuming they have an answer).

[Bluevitz-rs]

Does it only vibrate with the clutch out, or does the vibration go away with he clutch pushed in?

Sorry, didn't read the whole thread if someone asked this already.

[pb2k]

Constant vibration that scales with increased rpm. The slightly worn engine mounts dampened the engine idle vibration, leading to initial suspicion of the clutch or transmission, but I think we can now safely assume the problem is engine related.

The question is, what could so badly unbalance an engine without throwing a code or just outright destroying the engine?

[Bluevitz-rs]

Check the crank pulley to make sure it hasn't separated