Car popped out of first...

[DC2]

Today I was driving getting ready to park and all of the sudden my car popped out of gear.. I was in 1st gear probably around 2500 rpm and then all of the sudden 1st popped out and my rpms shot up to around 4k.. (accelerating)... I immediatly stopped and tried to figure out if I hurt anything. Well it seems to be fine now but i'm not 100% positive it is going into gear completly because all of the other gears feel notchy and when in completly you can hear the click from the tranny, but when I go into first you don't hear anything and it doesn't quite feel "in".

What possible problems am I looking at?
-Bent Shift Fork?
-Syncro's?
-Simple Driving Error

I have no idea but im confused, and lack much knowledge of how tranny's work? Should I start saving for a type-r tranny?
I have never launched the car since I got it, or raced it so I highly doubt it's from abuse.. It might have been I didn't push it in hard enough but I have never had a problem with it before.. I don't really push my car into gear very hard though and I was driving a good 600ft before it came outta gear.

[ChewiSi]

if this is the only time that this has happened to you it is more then likely that you just didn't push it in far enough. This has happened to me plenty of times because of my laziness.

[DC2]

but would the car drive for like 400 some odd feet before it did decide to pop out?

[ryanman]

yes

[Nate]

It could if it was in part way and the rpms stayed low I think.

Why were you driving in 1st at 2500 rpm for 400 ft? That's like 1.3 football fields.

[ryanman]

So people would hear his fart cannon, DUH.

[Redteg]

When was the last time you changed the tranny oil?

[DelSol93Si]

possible problems:

Low tranny fluid
bad syncro
bent shift fork
weak clutch
cold temperatures sometimes cause that too if the car hasnt been driven to get warmed up

[Weston-work]

Loose nut behind the steering wheel

[Aracheon]

:rofl: :rofl: :rofl: :rofl:

[ryanman]

laziness

[doctorstupid]

possible problems:

Low tranny fluid
bad syncro
bent shift fork
weak clutch
cold temperatures sometimes cause that too if the car hasnt been driven to get warmed up
No. For one, transmission OIL has no effect on the mechanical engagment of the dog teeth once engaged. Same with the clutch, and to be quite technical a "weak" clutch will only present an issue with clutch engagment, not clutch disengagment nor can it have any effect on an engaged synchronizer. None. Zero. Absolutely nothing to do with it. And typically cold temperatures will only be problematic when engaging a synchronizer as the cold oil will be very viscous and inhibit the friction rings from clearing it away for complete synchronization, often causing a grind. A worn ring will only exagerate the cold shifting condition. It is also worth noting that a synchronizer ring, just as the clutch and gear oil, can have no effect on an engaged synchro, either, it will only be problematic while engaging the synchronizer in question.

Aside from a bent fork leading to partial dog tooth engagment, a worn sleeve or dog teeth is probably the leading cause of popping out of gear. How many miles on the transmission? And do you make a habbit of downshifting into first while the car is still moving at or faster than 10-15MPH or so?

[STIBungy]

Low tranny fluid would cause 5th gear to pop out, intermittently.

No. For one, transmission OIL has no effect on the mechanical engagment of the dog teeth once engaged. Same with the clutch, and to be quite technical a "weak" clutch will only present an issue with clutch engagment, not clutch disengagment nor can it have any effect on an engaged synchronizer. None. Zero. Absolutely nothing to do with it. And typically cold temperatures will only be problematic when engaging a synchronizer as the cold oil will be very viscous and inhibit the friction rings from clearing it away for complete synchronization, often causing a grind. A worn ring will only exagerate the cold shifting condition. It is also worth noting that a synchronizer ring, just as the clutch and gear oil, can have no effect on an engaged synchro, either, it will only be problematic while engaging the synchronizer in question.

Aside from a bent fork leading to partial dog tooth engagment, a worn sleeve or dog teeth is probably the leading cause of popping out of gear. How many miles on the transmission? And do you make a habbit of downshifting into first while the car is still moving at or faster than 10-15MPH or so?

[Weston]

The synchronizer collars are what tends to wear on Honda transmissions, and they do in fact cause it to pop out of gear at times, as well as cause a crunching/grinding when going into gear.

[doctorstupid]

Low tranny fluid would cause 5th gear to pop out, intermittently.
In what transmission? A set of dog teeth is a set of dog teeth, regardless of which gear set it engages. Once the dogs are locked in, they aren't going anywhere regardless of lubrication. It's a direct mechanical engagment of teeth, gear oil doesn't hold them together.

Maybe the STi 6 speed is different, since it is a pressure fed system, however as far as I know it still relies entirely on mechanical dog tooth engagment, as do all manual synchronized transmissions.

[doctorstupid]

The synchronizer collars are what tends to wear on Honda transmissions, and they do in fact cause it to pop out of gear at times, as well as cause a crunching/grinding when going into gear.
The slider/sleeve/collar is, as I said, probably the leading cause of popping out of gear, aside from a bent fork/rail.

[Weston]

IN what transmission?

In every busted ass Honda transmission I have ever seen... if it has serious synchro issues, it will pop out of gear from time to time. Good tranny oil (namely Redline MTL) plays a noticable part in solving mild synchro issues... combine that with common sense, and it's quite reasonable to say that it's going to function worse when some parts aren't getting enough oil.

[doctorstupid]

In every busted ass Honda transmission I have ever seen... if it has serious synchro issues, it will pop out of gear from time to time. Good tranny oil (namely Redline MTL) plays a noticable part in solving mild synchro issues... combine that with common sense, and it's quite reasonable to say that it's going to function worse when some parts aren't getting enough oil.
There's a difference here, of course what oil you use will effect synchronizer wear and thus damage to the sleeve (which is the first part to be damaged when the friction ring starts to suck). However the oil does not hold the dogs in, thus low oil level cannot directly cause a gear to pop out. For a gear to pop out, the dogs need to either be not fully engaged (bent fork, rail or driver error), or damaged (caused by worn friction ring). If your sleeve has been damaged to the point it pops off the dog teeth, topping off your oil won't help you.

See what I'm saying? :)

[Weston]

There's a difference here, of course what oil you use will effect synchronizer wear and thus damage to the sleeve (which is the first part to be damaged when the friction ring starts to suck). However the oil does not hold the dogs in, thus low oil level cannot directly cause a gear to pop out. For a gear to pop out, the dogs need to either be not fully engaged (bent fork, rail or driver error), or damaged (caused by worn friction ring). If your sleeve has been damaged to the point it pops off the dog teeth, topping off your oil won't help you.

See what I'm saying? :)

I agree that there would have to be mechanical damage at that point, but having full oil or better oil may still help... it takes up space, and the problem here is that metal is missing and there's too much of a gap. Stuff like Redline MTL will stick to things a bit better to give it more of a coat. Aside from the protection that offers, it also helps fill gaps. And remember that they aren't really "locked" into place... if they were, you'd need some sort of release to pull it out of gear. Worn collar teeth just help it "fall" out of gear on it's own (or when it hits a sufficient bump). iirc, it seems to do it more frequently on left turns, but not so much on right (or vice versa), which indicates that the transmission oil could quite possibly be playing a part.

[DC2]

It could if it was in part way and the rpms stayed low I think.

Why were you driving in 1st at 2500 rpm for 400 ft? That's like 1.3 football fields.
because I was driving from one end of the safeway parking lot to the other because I work there and park in the far lot... We arnt really allowed to do over 10mph or we get yelled at by the manager so I just drove in nice and steady and than as soon as I got out of the parking lot it popped out.. So far the problem hasn't reoccured but thanks for the help guys, I learn something new every day on HAI.

[doctorstupid]

I agree that there would have to be mechanical damage at that point, but having full oil or better oil may still help... it takes up space, and the problem here is that metal is missing and there's too much of a gap. Stuff like Redline MTL will stick to things a bit better to give it more of a coat. Aside from the protection that offers, it also helps fill gaps. And remember that they aren't really "locked" into place... if they were, you'd need some sort of release to pull it out of gear. Worn collar teeth just help it "fall" out of gear on it's own (or when it hits a sufficient bump). iirc, it seems to do it more frequently on left turns, but not so much on right (or vice versa), which indicates that the transmission oil could quite possibly be playing a part.
Gaps or otherwise, no oil can replace metal. Here's the damaged slider from my old TSi AWD:

http://antisheep.org/hosted/FUBAR/slider2.jpg

http://antisheep.org/hosted/FUBAR/slider.jpg

Any applied torque and it came right out of gear. No oil can fix that, regardless of how thick of a coat it leaves on the hardparts. Liquids, no matter how viscous, are no substitute for case-hardened tool steel, if you're missing enough metal for it to pop out, oil is not the problem. Granted my slider is a bit worse than most, but it does serve to illustrate my point that no oil is going to fix that.

And on many transmissions the dogs are, quite literally, locked into place. the teeth are undercut, so that the slider teeth kind of go under the dogs completely stopping them from going backwards as long as torque is applied to the gear set; thus in order to take it out of gear load has to be removed from the gear set.

If your transmission has the capacity to fall out of gear, your detent springs are in desperate need of attention, again oil cannot help you here.

[doctorstupid]

Stuff like Redline MTL will stick to things a bit better to give it more of a coat
And come to think of it, assuming the transmission in question does not have under cut dogs, you would want as little oil on the dogs as possible to increase friction on the teeth, helping to prevent the sleeve from sliding back and disengaging. If something has a tendency to go the way you do not want it to go, lubricating it ( thus making it easier for it to go where it should not) does not really make sense, now does it? ;)

[STIBungy]

This was in my 89 Accord. The axle wasnt all the way in so it leaked some fluid. After I popped the axle in, I took it for a drive up hwy 93 and it constantly popped out of 5th gear. I got home and filled up the fluid and it stopped doing it.

In what transmission? A set of dog teeth is a set of dog teeth, regardless of which gear set it engages. Once the dogs are locked in, they aren't going anywhere regardless of lubrication. It's a direct mechanical engagment of teeth, gear oil doesn't hold them together.

Maybe the STi 6 speed is different, since it is a pressure fed system, however as far as I know it still relies entirely on mechanical dog tooth engagment, as do all manual synchronized transmissions.

[Dave_L]

This was in my 89 Accord. The axle wasnt all the way in so it leaked some fluid. After I popped the axle in, I took it for a drive up hwy 93 and it constantly popped out of 5th gear. I got home and filled up the fluid and it stopped doing it.
My integra did the same thing. I think the syncro was going out tho bc after a while it kept popping out of 5th even without low tranny fluid.

[doctorstupid]

My integra did the same thing. I think the syncro was going out tho bc after a while it kept popping out of 5th even without low tranny fluid.
At higher mileage once the dog teeth and sleeve have seena bit of wear and tear, a fatigued detent spring can cause a tranny to pop out of gear when shock loaded, or even under high load (WOT in high gear at low RPM, for example). But again, it's a problem in the synchronizer and detent, the only thing had to do with it was the wear on the synchro in the first place.

[Weston-work]

I don't see what you're still arguing... seems like we both agree. The problem is wear on the syncrho collar/sleeve/whatever-you-want-to-call-it. Just because someone said "synchro" doesn't mean they meant the brass part; the collar is just as important, actually more important.

[doctorstupid]

I don't see what you're still arguing... seems like we both agree. The problem is wear on the syncrho collar/sleeve/whatever-you-want-to-call-it. Just because someone said "synchro" doesn't mean they meant the brass part; the collar is just as important, actually more important.
Alright then :cool:

Although, in Hung's case it occured to me that the problem only showed itself with low oil because the oil acts as the transmissions coolant; because there is no actual cooling system in a tranny if the oil is low the gears will run quite a bit hotter. As they expand with heat, the backlash is taken up, which can cause enough resistance between the gears to "over power" a worn synchro, causing it to pop back off the dog teeth. Being in fifth when this happens is pretty nidicitive of it getting too hot, since the trans spins the fastest in 5th gear so it'll heat up pretty quickly. So low oil can make the problem noticable, I'll give you guys that :)