Apparently skipping gears kills synchro's

[mct75]

Hello all, just a quick PSA,

My daily drive involves pulling directly onto a busy highway from a stop. Typically I would need to take 1st nearly to redline, then 2nd and 3rd up around 3k or 4k, and once i'm doing flow of traffic, I calmly go from 3rd to 5th to commence cruising.

Apparently 5th doesn't like synchronising 4k rpm with 1800, for over a few thousand miles, 5th gear has completely worn down, and requires perfect revmatching to not grind. Woo.

I'm aware that such shifting loads the synchro's, but I've never had one be completely blown with less than 50k miles.

So to the other owners out there, take it easy. I already double clutch on all downshifts and shifts from neutral, but that still didn't save me.

Honda should take all of their transmission design team, put them on a plane, and then shoot it down.

[Eli]

Interesting. I guess it's kinda a "duh" thing, but it's crazy to see the actual effects from it. So essentially, shifting into 5th gear will now grind unless the RPMs are matched?! That's wild, and the first time I've heard of the Insight's synchros failing for an upshift. Makes sense though.

I've done the 1-2-5 shift plenty of times.. I guess I'll stop..

Honda should take all of their transmission design team, put them on a plane, and then shoot it down.

LOL.. I've been saying the same thing for years!

[Leeper]

I'd sure like to see some empirical data to back up your claim - on every car I've ever owned I've skipped gears, Insight inclusive, and NEVER had any issues nor have I ever heard of such a thing. I routinely go from 3-5 and back again (actually find 4th gear rarely used on my car). On a downhill I'll start in 2nd and shift right into 4th or 5th on any manual tranny. Also, I rarely redline first gear, no need as the gap between first and second isn't that great for me.

Can you back up your claim there with anything more than your own anecdotal experience?

[mct75]

It could be a fluke, but the other gears are fine.

And now, clutch-in coasting at 30 mph and sliding the shifter into and out of 5th makes the same sounds as trying to do it with the clutch out. Apparently there's zero cone clutch friction until the dogs start barking. I can double clutch into it just fine, so I'm confident it's the synchroniser. The cause is not certain, however I'd assume it's the loading from the speed mismatch.



Sadly the gearing and power bands of this car usually require a 1-2-5 to not be run off the roads. I always cringe too when I go into straight into second from a 10-15 mph autostop. I know that's not going to last forever, but double clutching usually returns it to autostop right at the instant I clutch in and shift into second. Can't make the engine too happy...

[Vigo]

Talking about synchro problems is a crapshoot because it all comes down to amorphous terms and honor code.

Sure, shifting from 3 to 5 or 2 to 5 shouldnt hurt the synchro, but it can, depending on how hard you push on it. The faster you try to put it in, the more it will wear the synchro. There's no way to know that someone didnt cause their own problems other than just believing what they tell you (honor code). In my experience as an auto tech, ive also noticed that most people dont notice or understand when they have clutch release problems, and will keep driving until they've burned through their synchros and then blame the transmission. I am not saying the op is lying or having a clutch issue.. just that threads about synchros can never tell you anything factual.

I have let my fiancee drive my Insight a few times to try to teach her how to drive a manual (bad car to learn on, i know). I always tell her, if the shifter gives you ANY resistance, STOP because YOU are doing something wrong. I usually accompany this by putting 1 finger straight down onto the top of the shift knob and shifting that way to show how little resistance there should be when you are doing it right (right placement and not going too fast, or not having the clutch fully released).

318k on original trans with no issues.

[Eli]

This makes a lot of sense to me, but of course it's anecdotal with only one report.

If you wind 2nd gear out to 4,000RPM and then shift into 5th, the synchro definitely has it's work cut out for it.

It could also be the clocking tab issue as seen in 1st and 2nd gears. Double clutching fixes this too, but the problem isn't with the synchronizer.

I guess the only way to tell would be to tear the transmission down....

[AbCaRed00]

If double clutching solves the problem then I'd guess synchros may be a big part of the problem too, as large trucks have big square cut gears and no synchros, and double clutching and waiting for the correct rpm 'roll off' is how they taught to shift in the driving schools. Now the gears in a tiny car are of course cut different etc etc but the principal of matching is the same. Short shifting won't necessarily kill the synchros but missing the correct timing will as said.

I used to acquire parts including more than a couple transmissions for my low budget ice racing efforts from the u-pick recycling yards, and as such it was sometimes the luck of the draw. A well smashed vehicle that was obviously running at the time of demise was generally a good donor, however, this was not always the case where a bad transmission could inadvertently be chosen.

One 'solution' was replacing the fluid with Redline Shockproof gear oil, containing the solid plastic beads which may help abate the grunchiness to some level. It would put a physical barrier of micro sized plastic beads between the metal parts. It won't cure, it will just make it a bit quieter and maybe easier to shift. It depends on how bad things have gone. Redline Shockproof worked for me in a small fwd 4x2 transmission in a competition vehicle with a bad second gear. Prior to putting the good stuff in we flushed with ATF for a few miles travel after draining the worst of the lumps out.

When draining the likely contaminated fluid from your Insight into a _well_cleaned_bucket, [if you want a good look at the fluid afterwards]... shine a light on the stream of oil as it drains and observe for any shiny chains of 'jewelry' are falling down in the stream. Little metal flakes and bits all in a line can light right up. That would be a sure sign of trouble. Gold color might be the remains of the synchros. Silver color, lots of other things. You could check what a magnet pulls out of the mix.

If you can capture some gear oil from your Insight into a sample container and send it off for analysis all the better but it would cost around a hundred bucks for an elemental analysis. That may be costly but would give a clue as to what is breaking. Sorting through the heavier parts of what was drained into the cleaned bucket may tell as much without going to great expense or effort. One thing that can tell if things are really far gone is the smell: the odor of burnt transmission fluid in one car's transmission oil we drained was particularly rank and pungent and indicated lots of heat.

Try some Redline shockproof gear oil, it's a bit more expensive, but the fluid's not too hard to replace and may help make it easier until you can line up a new transmission or rebuild/replace the parts required as need be.
I replaced my Insight's transmission fluid with the genuine Honda stuff earlier this year in my vehicle as the pic linked above demonstrates.

[Eli]

AbCaRed00, have you seen the thread on the clocking tab issue? The synchronizers aren't the problem with the 1st and 2nd downshifting issue, at least. I don't know about this 5th gear case.

I've been running Redline ShockProof Superlight in Insight #2 for a few thousand miles now. I love it. Makes the transmission feel really nice compared to my other cars. I've been meaning to put it in #3, too.

[AbCaRed00]

Originally Posted by Eli

AbCaRed00, have you seen the thread on the clocking tab issue? The synchronizers aren't the problem with the 1st and 2nd downshifting issue, at least. I don't know about this 5th gear case.

I've been running Redline ShockProof Superlight in Insight #2 for a few thousand miles now. I love it. Makes the transmission feel really nice compared to my other cars. I've been meaning to put it in #3, too.

Ya, saw the clocking tab modification. Good one. Downshifts to 2nd at 50mph sounds a bit of a torture test though imho. If it bears up and solves the problem that's the way they should be rebuilt.

Hard to say what the problem is on the fifth gear, draining fluid could tell and fluid replacement wouldn't cost too much relatively speaking.

As to cause, from left field kinda but:
I read in here somebody who cautioned about resting the hand on the stick when in gear underway as bad for synchro's, I guess he meant like stressing the gear by having the forks in contact inside the transmission. Not clear there but could be the case. It's a bad habit I've been able to break after jamming gears without using a clutch etc. Can't really see it doing much but maybe so if chronically leaning on it and it is very light built. I know I could make it buzz if I leaned on it in other vehicles. Could have been a few bad shifts or ??? .... tearing it apart would tell, if doing so may as well do the mod mentioned above then and there.
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I liked Redline products for the track vehicles but actually used MTL more often than shockproof in my street vehicles. I used to run Redline oil in the engine of one of my rides for some years, [still have some straight 40wt laying around] but as they have no detergents and I wanted to leave the oil in a bit longer on the street I stopped using it. Great products for performance to be sure.
The shockproof gear oil though lasted the life of the racecar's transmission and gave good results for the shifting. Never used it in a street car as my transmissions were never as bad to justify it. but for bang shifting at high rpm it was good.
Not sure if they've changed it or not but the type I used was pink with white beads that were visible to the naked eye.

[tadpole]

The Insight never came with How To Drive instructions, but if it did it would tell you to never use engine braking, use regen to the max to slow down. You can gently slide it into 2nd gear to take a corner, but then put it into the highest gear that will hold your desired speed. ( I go 2-5 all the time).Use max assist to accelerate, do not use high revs. I like the one finger on the shift knob method. I have seen too many drivers chunk from one gear to another like they are afraid to take an extra second to slip into the next gear. MCT75 sounds like he is beating up on his transmission.