I have a 93 accord lx that has a grind goin into 3rd gear at about 3-4k.

I opened the tranny tonight and the synchro spring is round and looks fine, the synchro sleeve teeth on the 3rd gear have a good point on them, and the syncro sleeve and hub slide smoothly. I didnt disassemble the gear set yet but I will tomorrow.

When i drained the tranny oil I saw brass flakes in it and with the tranny cover off i see some brass flakes on the mainshaft. When I did a search here on HT and looked through the FAQs on this tranny forum, I saw pictures of synchros and gears rounded out and visually you can see the damage, but as i'm comparing my 3-4 synchro set to my other ones everything looks good.

Could the inside of my synchro ring where it presses onto the 3rd gear be worn causing the flakes in my oil and grinding????????

 

Yes, but if its causing that many flakes, the gear cone is probably worn. Check clearance between bottom of synchro and top of gear teeth. Take a look at the slider teeth to see how worn they are. If they're rounded they will cause a grind.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aquafina &raquo;</TD></TR><TR><TD CLASS="quote">Yes, but if its causing that many flakes, the gear cone is probably worn. Check clearance between bottom of synchro and top of gear teeth. Take a look at the slider teeth to see how worn they are. If they're rounded they will cause a grind.</TD></TR></TABLE>

Slider teeth? as in the synchro sleeve and hub teeth?

I didnt check the clearence on the synchro to top of the gear yet but it looks ok, its suppose to be around .84-1.1mm i'm guessing, cuz I looked through my civic helms manual and the specs were close to that.

Is the gear cone part of the 3rd gear?

 

Check the clearance. Can't tell just by looking.

Teeth on the sleeve yes.

Gear cone is the polished part of the gear that the synchro sits on.

 

Ok, yeah I will measure it when I get home tonight. If the clearence comes out too low, that could be the inside of the synchro worn out or it could be the gear cone worn right?

If the syncho is worn I can probably tell by looking at it but How will i know if the gear cone is worn without a new synchro to measure the clearence with?

Aquafina: where did you get that avatar pic, I've been trying to find a polish flag with eagle on it and i can't.

 

Measure between the bottom of the synchro and top of the gear. Not between the synchro and gear cone. Gear cone shouldn't be worn.

Stole it from TYPERMAN2001. Polish coat of arms. 50% Polish here.

 

Ok thanks, I do all the measuring and checking tonight.

Yeah I'm 100% polish and I love avatar, but I don't want the same thing you have. I have to google some flags.

 

lol I've got it tattoo'd on my upper back. I need to find a nice Polish girl to get the bloodline back up . Ok, I'm done with the OT, post up the results tonight.

 

Ok Ok Ok, I'm kinda excited cuz after staring and playing the synchro assy, i think i know how it all works.

First, I checked the clearences and they were around .80mm, which seemed low, but I checked the 4th and 2nd gear to synchro clearence and they were all the same.

Second, THE DAMAGE: I removed the 3-4 synchro hub and sleeve, and I found the corners rounded off on the 3rd gear side of the synchro sleeve. Which is casuing my grind right?? LET ME TRY AND see if I can explain why its causing a grind and you can correct me if i'm wrong..


As I see it, when the shift fork pulls down on the SYNCHRO SLEEVE, the teeth inside are putting temporary pressure on the SYNCHRO RING, which causes the SYNCHRO GEAR to bite into the 3rd gear cone. CORRECT??????

But in my case since the teeth on my SYNCHRO SLEEVE are worn and rounded they are slipping pass the SYNCHRO RING causing the SYNCHRO GEAR not to bite into the 3rd gear causing my grind.

Sorry for this lengthy post but please correct me if i'm wrong. And please reply with the quickness so i can start ordering this stuff from honda.

 

Somewhat close. Shift fork pulls the slider down, the valley part of the teeth on the slider slide over the teeth on the synchro. The synchro has a slight interference fit with the gear cone, this slows the gear down so the slider can line up and slide over the dog teeth on the gear.

When the slider teeth are rounded, they grind on the synchro teeth and gear dog teeth. Usually it will enage the synchro quick enough to not damage it, which is why the dog teeth on the gear will wear. Clutch all the way in before you start the shift. Clutch out once the shift is complete. That will help a lot with wear prevention.

 

Ok, so what your saying is this wear I have on the synchro sleeve is due to not compressing the clutch pedal all the way before shifting?? And If I replace the synchro sleeve, hub, syncro ring and spring assy as sold together from honda, will it solve my problem??

I just bought this accord a month ago on craigslist, i new it had a 3rd gear grind and i was just gonna repace the tranny with another one from a junk yard, but I figure i did't want to install the tranny and have a different problem with it. Plus I had my b16a tranny open for a 4.785 fd install so I figure i'll give this grind issue a try.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hondadriver &raquo;</TD></TR><TR><TD CLASS="quote">Ok, so what your saying is this wear I have on the synchro sleeve is due to not compressing the clutch pedal all the way before shifting??</TD></TR></TABLE>

When you have moving parts making contact, something needs to wear....in most cases, the sleeve wears first....

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
And If I replace the synchro sleeve, hub, syncro ring and spring assy as sold together from honda, will it solve my problem?? </TD></TR></TABLE> Sounds like the only issue, so yes. I would replace the mainshaft bearings as well

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">

I just bought this accord a month ago on craigslist, i new it had a 3rd gear grind and i was just gonna repace the tranny with another one from a junk yard, but I figure i did't want to install the tranny and have a different problem with it. Plus I had my b16a tranny open for a 4.785 fd install so I figure i'll give this grind issue a try.</TD></TR></TABLE>

Nice...good work

 

If you're going to drive the car for a long time and it is high mileage, I'd go ahead and replace all the needle bearings. They like to eat up gears when they break and the gear seizes on the shaft.

 

Alright, i installed the new 3-4 synchro assy, put the tranny back together this weekend, installed it in the car and i took it for a test drive tonight. And the problem is solved, the tranny shifts smooth and NO MORE GRIND.

Thanks for the help and info................................

 

SOmetimes even if the cone is ok the sycro will "bottom out" on the respective gear... without any grip slowing the gear down... you can check for it by tryong to press the syunc all the way down against its gear, if theres no clearance, theres a problem

 

Thats why I told him to check the clearance.