Synchros gone?

[PandaBear]

Friend who track his supercharged civic had a transmission that feels like a slipped clutch, but upon inspection at his mechanic they found lots of loose metal in the drained tranny fluid. He though it might be a broken 1st gear synchros and want to replace the broken ones only.

My thinking is that he should have just get a complete rebuild because these loose metal may have damaged other synchros or bearings, does that make sense?

 

[bepperb]

I can't imaging going to all the work of dropping and cracking the tranny and not replacing everything. I'd even be tempted to get the flywheel surfaced and a new clutch. But, to each their own.

 

[willix]

It may be a differential pin failure in the works. This will explode the trans when the finally fails. If thats the issue. What is the metal in the oil? Syncro rings are usually brass/bronze or plastic. A diff pin will wear on the case and put aluminum in the oil.

 

[fsskier]

Feels like a slipped clutch??? Tell us more!! When you lose a synchro you may not be able to shift into a gear without grinding ( unless you are familiar with the double clutching technique) but once the gear is engaged all will be normal. If it "slips" when in gear, then something is bad broke!!

Once the gear box is taken out and disassembled the labor is already paid for..... not much chance to save there.

Loose metal in the oil: If you knock a couple of large chunks off, they just fall to the bottom and stay there usually. If its small flakes, particles and chips..... damage to many of the internal parts may happen.

 

[ryan2022]

A broken first gear synchro seems unlikely.

Hondas usually suffer in 2nd or 3rd gear. Mainly 3rd.

If the case is apart, I'd have them replace the 2nd and 3rd gear synchro as well, and take a GOOD look at everything else.

In most cases you'd hear a bad bearing.

Was the metal they found gold?

Honestly, if you havent dealt with these guys before, tell your friend to be carefull.

I'd suggest swapping in some GM synchromesh or Amsoil Synchromesh MTF and run it the way it is with a fresh clutch.

A manual transmission usually wont slip. It may not engage, pop out of gear, make a lot of noise, grind, etc... but its generally the clutch that will slip, especially in a supercharged engine........and if the clutch is stock.

 

[DieselTech]

Originally Posted By: willix
It may be a differential pin failure in the works. This will explode the trans when the finally fails. If thats the issue. What is the metal in the oil? Syncro rings are usually brass/bronze or plastic. A diff pin will wear on the case and put aluminum in the oil.


+1 what was the material found.

If it comes apart i vote Carbon Fiber syncs. No distortion under heat and retain perfect geometry. They are expensive but I have just awesome results using them in ZF's

 

[440Magnum]

Synchro symptoms: grinding gears when trying to engage a gear, lever feels "blocked" and won't go into gear.

Slippling clutch symptoms: Engine RPM rises with no change in road speed under certain conditions (open throttle when engine is near its peak torque RPM).

They aren't the same symptoms. Stripped splines somewhere internal to the gearbox or differential could act like a slipping clutch... for a little while. Very soon it would start acting like a clutch that wouldn't engage at all.

 

[Kestas]

Is the metal debris magnetic?

 

[PandaBear]

Thats what he said on his message:

I thought I burnt the clutch. It slips hard on the 1st gear when the car take off. Took it to machanic for a check up and found lots of loose metals in the transmission fluid. Prob. the syncros on the 1st gear is gone?! Time for a rebuild. Its getting hard to reach the next event.

I'll ask him more about the details.

 

[defektes]

If hes going to drop the trans, do a complete rebuild, replace the clutch and resurface the flywheel. In addition bleed the clutch with some new fluid.

 

[PandaBear]

Here is what he said in another internet forum (honda-tech):

Quote:

The symptom after the track event is this:
All gears shift smoothly (well, maybe the reverse has a little struggle, maybe once a week? It's been like that). When the 1st gear meet the engagement point and step on the gas pedal, the car struggle to move and the engine/transmission (not sure exactly where the noise comes from, but should be somewhere they closely connected) make loud noise. The struggle as if it were some form of slipping from an engagement.

I personally saw those silver loose metals but I am not aware if there would be brass/bronze metal as well because the oil is still fresh and metals were coated with oil. As far as my limited knowledge about Civic, none of the EG/EH Civic comes with a factory diff. So, something got to be wrong with the tranny?!

The car is still drivable but I perfer not to. I have to slowly engage the 1st gear and step on the gas pedal after the gear is *fully* engaged, not at the engagment point.

 

[wantin150]

Any chance the metal is the rivets from the clutch facing?

 

[Audi Junkie]

Define "lots" of metal.

 

[willix]

Throw out bearing drag can cause difficult shifting and will wear on the PP diaphram fingers to a point of total diaphram failure. Reverse & 1st usually not synced. So this has a aftermarket limited slip diff? Open diffs hate tire spin and at the track, on turn out tire spin can be difficult to control.

 

[PandaBear]

As far as I know the definition of "lots of metal" to him is more than a couple pieces, something that you'll notice when you change the fluid.

I don't think it has a limited slip in it.

 

[willix]

It says in the quote "none of the EG/EH civics come with a factory diff". I don't know EG/EH what that is. So I ask. Also, to have a blown induction really puts the drive line to the test. Tire spin is a huge problem on these little cars. I don't know this Honda fwd 5 speed but it can't be that much different than the rest. Some(the good ones) aftermarket limited slip diffs have a clutch pack in them. They share oil with the trans. The wrong oil can cause problems.

 

[PandaBear]

Originally Posted By: willix
It says in the quote "none of the EG/EH civics come with a factory diff". I don't know EG/EH what that is. So I ask. Also, to have a blown induction really puts the drive line to the test. Tire spin is a huge problem on these little cars. I don't know this Honda fwd 5 speed but it can't be that much different than the rest. Some(the good ones) aftermarket limited slip diffs have a clutch pack in them. They share oil with the trans. The wrong oil can cause problems.


My understanding is EG/EH is the late 90s civic CX/DX platform. The stock motor is probably about 90-100hp, just a WAG after the supercharger it is going to be 140hp, and my understanding is that these tranny isn't design to be supercharged and therefore he blown it.

The thing we don't know is whether it is ever going to be good to just do a stock rebuild, or if this tranny can be build to support a super charger at all, thus make it a waste of money.

 

[willix]

Well for starters the clutch & the diff are the only reasonable upgrades possible. There is a Quaife differential on ebay for $500 and thats about as cheap as he will find. Quaife the best one out there. A new one is around $1000 This is the best upgrade on can do to a FWD trans. That will solve a major weak link in the drive line. Next is the clutch. As I said before spinning the tires is the enemy of a open diff. with a Quaife you can spin off all the rubber you want & it will hold up. So the blower adds 40hp or 140hp? I find that if you don't try to speed shift the gear hardware holds up pretty good in the light trans. You can't cram helical gears.

 

[u3b3rg33k]

Originally Posted By: PandaBear

My understanding is EG/EH is the late 90s civic CX/DX platform. The stock motor is probably about 90-100hp, just a WAG after the supercharger it is going to be 140hp, and my understanding is that these tranny isn't design to be supercharged and therefore he blown it.



I can't see an extra 40 horsepower breaking a transmission. Figure out what it's torque rating is.
Repeated hard launches is another matter entirely. The instantaneous torque is far beyond the constant torque that the engine can apply.

Originally Posted By: willix
Well for starters the clutch & the diff are the only reasonable upgrades possible. There is a Quaife differential on ebay for $500 and thats about as cheap as he will find. Quaife the best one out there. A new one is around $1000 This is the best upgrade on can do to a FWD trans. That will solve a major weak link in the drive line. Next is the clutch. As I said before spinning the tires is the enemy of a open diff. with a Quaife you can spin off all the rubber you want & it will hold up. So the blower adds 40hp or 140hp? I find that if you don't try to speed shift the gear hardware holds up pretty good in the light trans. You can't cram helical gears.


If you do go with an aftermarket diff, I highly recommend a quaiffe / torsen diff.

I put a torsen in my car two months ago, replacing a tired out clutch pack diff, and it's worlds different, especially in the snow and at ice events.

 

[PandaBear]

The SC is adding 40 hp (according to common info), it is a 1.6L so it won't add another 140 for sure.

My guess is that he is hard launching this tranny, definitely not the gentle daily driving. There is probably no way a small transmission can take that much abuse, and people who need a stronger setup usually go with the DOHC B series motor/transmission from Civic SI or Integra (that's why there are so many stolen Integra).