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Discussion Starter #1
2015 Scion TC
I was driving the other day and accidentally shifted from 4th to 3rd gear instead of 5th gear going about 50mph. My daughter often drives this car and had me thinking, could she accidentally mis-shift from 4th to 1st gear? Is there any kind of safety features that would prevent her from putting it into first? If she did shift into first going 50mph would the Rev limiter keep the engine from blowing up, or would the low first gear drive the motor to over rev?

Thanks!
 

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2002 Ford Focus SE
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Not familiar with the car, but making some guesses ...

Generally, I don't think there is a lockout to prevent you from going from 4th to 1st.

If there is a rev-limiter on the engine, it should cut it - whether it reacts in time and how it works, I'm not sure.

In general, you would know if you did that if you drive a stick at all. For example, I'm sure you expected the RPM's to go down when you put it into 5th gear - if they went up, you knew you picked the wrong gear. Hopefully if she expected to shift to 3rd and the RPM headed for 7K - she would know to drop the clutch and shift to the gear she intended.

The only time I have really had an issue with selecting the wrong gear was on some cars where reverse and 1st were close together and I was starting from a stop (or Reverse and 4th or 5th - depending on the pattern).
 

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It is certainly possible to mis-shift with a manual transmission, causing major engine/exhaust damage. The rev limiter would likely not help much if you actually managed to shift to first at highway speeds. I would think it would actually be quite difficult to make such a mistake though, you'd have to move the shifter quite a bit and you'd have to double clutch it (shift to neutral, then shift to first, or rev match it I suppose...), and the second you dropped the clutch it would be seriously chaotic, such that one would be pressing the clutch in again immediately.

If any damage was caused it would be permanent and apparent right away though.

If you're concerned your daughter is that bad at driving manual, just have her stop driving it.
 

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straight cash homie
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I think not. There are a lot more safeguards in newer vehicles these days that will prevent you from blowing up the car in case you mis-shift. Obviously, you're not trying to purposely shift in the wrong gear so the long-term effect would be nil.

If your daughter is driving a stick shift, she is impressive already...dad go get the shot gun.
 

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Discussion Starter #5
Thanks yeah I would be surprised if anyone made that big of a mistake. I don't think she would, but it just had me thinking about the mechanics of it.
 

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2002 Ford Focus SE
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As mentioned, the mechanics of it cue you in - if you expect to drop to 3rd and be at 4K or so RPM to slow the car down and suddenly it is up around 6K as you let the clutch out, most people will instinctively re-depress the clutch and select the correct gear.
 

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Discussion Starter #7
I think not. There are a lot more safeguards in newer vehicles these days that will prevent you from blowing up the car in case you mis-shift. Obviously, you're not trying to purposely shift in the wrong gear so the long-term effect would be nil.

If your daughter is driving a stick shift, she is impressive already...dad go get the shot gun.
LOL!!!! One step ahead of you. I appreciate it. I was just thinking about it and wondered about the mechanics of it. It would definitely be a highly unlikely scenario, but what if?
 

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Don't know about the TC, but the synchromesh for C60 transmission in my 2ZZ-GE XRS locks the first gear out every time the speed goes above 15 km/h (9 mph) and the only way anyone can downshift into that gear above that speed, is through double-clutching.
 

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I think not. There are a lot more safeguards in newer vehicles these days that will prevent you from blowing up the car in case you mis-shift. Obviously, you're not trying to purposely shift in the wrong gear so the long-term effect would be nil.

If your daughter is driving a stick shift, she is impressive already...dad go get the shot gun.
All you really have is the syncros to "stop" you from making such a mistake. Trying to shift into a lower gear would be difficult because of the speed differences. That's why you'd feel some physical resistance trying to shift in. But depending on the type of car (I haven't tried in a 15 TC) it wouldn't take that much effort. And once you drop the clutch all bets are off, a combination several things could happen. Worst case senario the drive wheels could lock up, causing a serious loss of control. In a panic, an inexperienced driver wouldn't know what to do (hence all the "unintended acceleration" crashes).

The sudden increase of RPMs would quite possibly overwhelm the rev limiter, causing top and or bottom end damage (valves could collide with pistons). Whether you did it on purpose or not doesn't really matter, the motor would be seriously damaged.

The reason why the rev limiter wouldn't help, most of them work by either cutting fuel or spark. In this case, that wouldn't stop the engine from turning over. The momentum of the vehicle is causing the drive train to turn, the transmission is multiplying that momentum tremendously in 1st gear, and the engine is directly connected through the clutch. There's no safety nanny to help out here, it's just physics.
 

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Toyota may have put some kind of protection in considering the market audience of the car and the lesson they learned the hard way with the Celica GT-S.....

Most misses occcur going from 2nd to 3rd(back to 1st) or from 3rd to 4th(back to 2nd) as people are hurrying to get a gear to keep up with traffic.
If you're just driving normally, the RPM's usually aren't high enough to jump over the redline and do any damage, but if you're racing the engine, shifting at redline and drop back to the wrong gear, you'll end up with an air conditioned block or broken valves and the such.

I've seen RSX's missed and hitting 12k on the tach. we had a Celica GT-S come in with the last known RPM clocked at over 14k before it blew.
 

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Don't know about the TC, but the synchromesh for C60 transmission in my 2ZZ-GE XRS locks the first gear out every time the speed goes above 15 km/h (9 mph) and the only way anyone can downshift into that gear above that speed, is through double-clutching.
there's no "lockout" it's just that you'll fry the synchros and have to force it. more speed difference = more resistance. See below.
All you really have is the syncros to "stop" you from making such a mistake. Trying to shift into a lower gear would be difficult because of the speed differences. That's why you'd feel some physical resistance trying to shift in. But depending on the type of car (I haven't tried in a 15 TC) it wouldn't take that much effort. And once you drop the clutch all bets are off, a combination several things could happen. Worst case senario the drive wheels could lock up, causing a serious loss of control. In a panic, an inexperienced driver wouldn't know what to do (hence all the "unintended acceleration" crashes).

The sudden increase of RPMs would quite possibly overwhelm the rev limiter, causing top and or bottom end damage (valves could collide with pistons). Whether you did it on purpose or not doesn't really matter, the motor would be seriously damaged.

The reason why the rev limiter wouldn't help, most of them work by either cutting fuel or spark. In this case, that wouldn't stop the engine from turning over. The momentum of the vehicle is causing the drive train to turn, the transmission is multiplying that momentum tremendously in 1st gear, and the engine is directly connected through the clutch. There's no safety nanny to help out here, it's just physics.
Correct, the rev limiter ONLY affects rpm initiated by the skinny pedal. If you stick it in 1st while driving too fast and let out the clutch, the ECM can cut fuel, spark, and throttle but those aren't what's driving the engine speed.

Long story short, the daughter might push the stick in the wrong direction, but she'd have to push really hard and chew up the synchros long before it actually went into 1st.
 

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Discussion Starter #12 (Edited)
Well to tell the truth that's not what happened. I didn't want to tell the real story because It's an ongoing story and really I wanted the technical aspect of it. And you all have basically said what I've thought. Here is the short story.

My daughter is actually 22 yrs old and has been driving a standard since she got her first car 7 years ago. She bought a BRAND NEW 2015 Scion TC with six speed manual in January 2015. Between driving to work, school, and where ever else she goes, she has put 21k miles on it as of thanksgiving day. She knows this car very well hint 21k miles in 11 months. Two other Scion manual transmission drivers were with her in the car when the events happened.

Thanksgiving day she was driving on a road normal increasing her speed (40-50mph) and shifted from 4th going into 5th gear. She said the car kind of hesitated and then shut off while going 40-50mph. She pulled over on the shoulder. Her boyfriend (26yrs also TC owner with manual) got in the driver seat and tried to start the car because they weren't sure what happened. Wouldn't start and wouldn't turn over. Towed to dealer.

Long story short, the dealer says the engine was shot and they wouldn't cover it under warranty because it was cause by the engine being "over-revved" which can only happen by "mis-shifting." But they had no freeze frame showing the event or showing the engine rpms over revving(one mechanic said 12,000rpms) saying the freeze frame got lost when her boyfriend tried to start the car on the side of the road. (THIS IS NOT HOW MY DAUGHTER AND HER WITNESSES DESCRIBE THE EVENT, THE ENGINE DIDN'T REV AT ALL, SHE DIDN'T MISSHIFT. If you went from 4th to 3rd, the engine wouldn't have blown, and there is no way she shifted from 4th to 1st with her experience. But the dealer mechanics say this is the "ONLY" way this could have happened. The rocker arms came off and the "buckets or shims" came off and dropped down in the cylinders and shredded into the oil pan. They put the engine back together and luckily it started and drove ok with new buckets.

The price for all of this was $750.00(surprising it was this cheap) After going in circles with the warranty department they offer to cover $500 of it by "goodwill," but will mail her the $500 in a couple of months after we pay the initial bill. Not good enough for us considering this is a fairly new car, and now we don't know how the engine really is after grinding and chewing up those buckets, and plus not really knowing what caused this, they say she did, 3 of us say it didn't happen like the way they are saying. Is this engine still reliable? Is my daughter gonna get killed the next time this happens and her car is struck by an 18 wheeler? The car has been at the dealer since thanksgiving. We will not pay. And neither will they.

Now she has a meeting set up with a arbitrator and the dealer on the Jan 19. I guess the arbitrator will hear both sides. I wanted to print some comments from theses message boards showing that it is pretty much impossible to shift from 4th to 1st(only way the eng would blow) UNLESS she did it on purpose and and forced it into first gear, which she wouldn't do because she works her ass off for this car. Also will have both witnesses there. Since Toyota has payed the arbitrator to show up, I'm not expecting it to go in my daughters favor, so she will contact a lawyer at that point.

It's just so UNBELIEVABLE that Toyota/Scion would put their customers through something like this for $750. The only proof they have, is a mechanic saying this is the "ONLY" way this could happen. No freeze frame no nothing. And we have 3experienced manual transmission drivers saying this is not at all how it happened.

Any comments or tips? Thanks, sorry it was so long, that's why I told the original story just to get the mechanical comments.
 

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2002 Ford Focus SE
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Any comments or tips?
Comments -

Wish you'd told the honest story originally.

Really surprised they did all that work for $750 and dropped that price to $250.

Surprised if it hit 12K RPM and "all" they had to do was bolt the buckets back on and it ran fine.

Tips:

We can't help you. Some of us individually can, but saying "I asked online and a bunch or car guys said it can't happen won't impress an arbiter. Your lawyer needs to get some expert witnesses. (Might be guys that he pays to memorize and repeat what is posted above, but ...)
 

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Discussion Starter #14
Comments -

Wish you'd told the honest story originally.

Really surprised they did all that work for $750 and dropped that price to $250.

Surprised if it hit 12K RPM and "all" they had to do was bolt the buckets back on and it ran fine.

Tips:

We can't help you. Some of us individually can, but saying "I asked online and a bunch or car guys said it can't happen won't impress an arbiter. Your lawyer needs to get some expert witnesses. (Might be guys that he pays to memorize and repeat what is posted above, but ...)
Yeah sorry like I said I just wanted the technical talk, not people giving me lawyer advice and I was pressed for time when I made the original post. As you can see it took me a good 30 mins to type all this out.
 

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Don't use anything we say with an arbitrator. if anything they will use us against you. Quoting us is about as good as quoting Wikipedia as a source for a research paper.

No offense, but you're better off using what you've read to come up with questions on your own to help prove your story.
 

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Agreed with the above advice. You don't need to know the "technicals" here honestly. The manufacturer needs to prove that she caused the defect, that's going to be very hard to do assuming the arbitrator is fair. Not giving any legal advice, but I would venture to guess the LESS you say the better. The burden of proof is on them.
 

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if they're telling you the "rocker arms" came off, they're feeding you a HUGE lie. the only toyota engine with rocker arms is the one they use in NASCAR. all toyota engines sold in the last 10 (maybe even 20) years are dual overhead cam, where the lobes of the camshaft operate directly on the valve lifters (which ARE sometimes called "shim buckets" since they resemble small cups and have shims on top of them). even if it DID have rockers (which it doesn't), there's no possible way for them to "fall into the cylinder" because the cylinder head is in the way.

now it IS possible that if the engine actualy did over-rev, it could have broken a valve or two, and THAT could rattle around in the cylinder, scratch the walls, and ding up the piston (and the dome of the cylinder head). but i seriously doubt you'd get away with valve replacement and cylinder reconditioning for under a grand. more likely though would be a broken rod, hole in the side of the block, major oil loss, smoke, etc. obviously none of that happened either, because a thrown rod generally means new engine (or at least a new short block, which is normally a couple grand).

it's possible there was a spun bearing, which has NOTHING to do with high revs and more to do with low/no oil. when that happens, generally the engine seizes up and when you try to restart it, it just clicks and does nothing. again, that usually means motor time and big money.

from what i'm reading here, this sounds fishy.

but yes, taking legal advice from the interwebs is not ideal. but if you have a better idea of how an engine is put together, you'll have better odds in case the arbiter isn't as neutral as he/she should be.

oh, and in my decade or more of driving stick, i've never been able to put anything (2 different camrys, a miata, an x-runner, and plenty of customer vehicles from when i was a toyota mechanic) back into first while i'm still moving unless i double-clutch AND rev-match. which if you're shifting UP a gear, you would never do.
 

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if they're telling you the "rocker arms" came off, they're feeding you a HUGE lie. the only toyota engine with rocker arms is the one they use in NASCAR. all toyota engines sold in the last 10 (maybe even 20) years are dual overhead cam, where the lobes of the camshaft operate directly on the valve lifters (which ARE sometimes called "shim buckets" since they resemble small cups and have shims on top of them). even if it DID have rockers (which it doesn't), there's no possible way for them to "fall into the cylinder" because the cylinder head is in the way.

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Actually, it does. For NVH reduction, less energy loss/wear due to friction, and automatic valve lash adjustment the 2ARFE is equipped with roller rockers with a hydraulic lash adjuster. The old style system is mostly relegated to older engines and economy motors, mainly because they're noisy, you have more friction (creating energy loss), and may wind up needing adjustment (never had to do this) due to wear. I could easily see over revving damaging these even if I also think it'd ruin a bearing or break a valve spring first.

As for legal advice, I won't give any either at this point. However, I would make sure that they realize the burden of proof is on them to prove the engine was damaged by a missed shift and that goes back to the data logs on the computer.
 

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Stock? Blasphemy!
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ok, i'll admit i haven't been inside an engine made since 2003, so you're probably right.

still think the whole thing sounds fishy. course we can't really say what happened since we didn't see the inside of that motor, so it's really hard to say. but that price does sound awful low for the amount of work they claim to have done. even at $750.
 

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sdoyle21 said:
The rocker arms came off and the "buckets or shims" came off and dropped down in the cylinders and shredded into the oil pan. They put the engine back together and luckily it started and drove ok with new buckets.
Easy question. Ask them how this is possible since NONE of those parts have any access to the inside of the cylinder. in fact, it's not physically possible for this to happen.
Also, ask how all of this happened without causing irreparable damage to the inside of the cylinder walls.

Please do me this. can you scan a copy of your repair order(cross off all non-essential information, address, dealer name, etc...) and post it here so we can see exactly what was done, tech storys, and the such?

If not, can you PM me this info?
 
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