i came across this post and was wondering what you guys think.
to me it sounds like this would mess up your tranny even more.
any thoughs on what is actually going on here?

http://www.team-integra.net/fo...ion=1





Modified by THE LORD OF CHAOS at 1:52 PM 10/31/2006

 

im skeptical but many people say it works. The real solution is to replace the synchro and or sleeve set

 

Im not positive how that really works but I think a synchro works by making contact with a gear before the teeth on the synchro and the teeth on the gear engage. This gets the synchro spinning at the same speed as the gear and allows the teeth to mesh.

So possibly, just possibly, by doing what the OP suggested, you're "freeing" up the frictional contact point? (where by freeing up, i mean making it easier for the contact pt to spin)



Modified by Jeterkm02 at 9:16 PM 10/31/2006

 

You can either take my word that It's a bad idea, or you can read below and I will prove to you that it's a bad idea.

here's the inside of a synchro.


here's a gear, see the gear cone? it's the smooth shiny surface with the "hair" on it



the synchro hub is locked to the shaft (3-4-5 gears it's on the mainshaft, 1-2 gears it's on the countershaft) the synchro sleeve is splined and slides up and down on the synchro hub. Synchro sleeve is always at same rpm as synchro hub.



for example, lets use a bone stock d16z6 trans. 1st gear is 3.25, 2nd gear is 1.9, final drive is 4.25.

Take 1st gear to 15mph (3000rpm) then shift to 2nd. While in 1st gear, countershaft 1st is locked to the 1-2 synchro hub and spinning 923rpm. Meanwhile, countershaft 2nd gear is chilling at 1579rpm. When you shift from 1st to 2nd (assuming that you're not double clutching) The 2nd gear synchro is spinning at a 656rpm difference between 2nd gear's rpm. The synchros job is to slow 2nd gear down to the right speed so that the synchro sleeve teeth can lock onto the gear.

656 eh? That's nothing.

Take 1st gear up to 7500rpm. Countershaft 1st is spinning at 2308rpm, along with the 1-2 synchro hub. Shift to 2nd. Countershaft 2nd gear is spinning at 3947rpm. In the split second (no pun intended ) It is the synchros job to slow the countershaft 2nd gear down to 2308rpm.

3947 - 2308rpm = 1639. <FONT SIZE="3">Between shifts 2nd gear is 1639rpm out of sync. synchro bites down on the gear cone and matches the speed. Once the synchros wear out (can't bite down hard/fast enough on the gear cone) it can't slow the gear down enough, so then the teeth on the synchro sleeve hit the dog teeth on the gear to slow it down. This is bad, this is what you hear when gears grind. Remember the first picture I posted up there, with the insides of the new synchro? Think about those brass ribs wearing smooth. Synchro isn't going to be able to slow the gear down in time, therefore grinding your synchro sleeve teeth and dog teeth.</FONT>

 

So bense, excuse me if I didnt figure it out from your post, but what exactly is happening when you apply pressure to shift into a gear (enough to a point just before an audible grind occurs), meanwhile revving the motor at 4k with the clutch engaged? Are you wearing out the brass ribs inside the synchro?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jeterkm02 &raquo;</TD></TR><TR><TD CLASS="quote">So bense, excuse me if I didnt figure it out from your post, but what exactly is happening when you apply pressure to shift into a gear (enough to a point just before an audible grind occurs), meanwhile revving the motor at 4k with the clutch engaged? Are you wearing out the brass ribs inside the synchro?</TD></TR></TABLE>

yup.

 

ill report back in 15 min. i am going to try it on my ls tranny, 3rd grinds above 3200rmp

 

cure= GM syncromesh W/ friction modifier.

 

When you move the gear selector slightly up into a gear slot to partially engage the gear position, it will grab and spin the synchro ring first, but doesn't move the synchro ring far up (or down) enough to grab and spin the gear. The gear free floats while the hub, sleeve, and engaged synchro ring spin at the speed of the counter or main shaft.

I don't really see how it works either, to do anything except to put more wear on the synchro and gear. Who knows at this point, maybe this purported build-up really is a true phenomenon.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fastwanabe &raquo;</TD></TR><TR><TD CLASS="quote">cure= GM syncromesh W/ friction modifier.</TD></TR></TABLE>

no.

cure = replace worn parts.

 

this should be in the tranny forum!! Oh wait

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HT Chaplain &raquo;</TD></TR><TR><TD CLASS="quote">this should be in the tranny forum!! Oh wait </TD></TR></TABLE>

this pretty much is becoming the tranny forum.

tech/misc has more trans threads in it than the eg/ek forum has worthless threads.

 

I posted in that thread on team-integra and it worked on my 94 Integra which is my daily driver.

Obviously it may not be a "good" fix, but it did cure the grinding issue.

 

put it this way.....

if it works, great you dont have to rip apart your car, mess with the tranny ripping it apart, spend 300$ or so on a sleeve set to get rid of the grind.

If it doesnt work, oh well you had a grind to begin with and are in the same boat id say its worth a try before going thru all that work and $$

 

Its purpose is to burnish the synchro on the gear that's having problems engaging. It's actually a recommendation in the Dec 99 Acura Service News-

"On an M/T vehicle with less than 2,000 miles, you
can sometimes fix a shift grind by burnishing the
offending gear’s synchronizer. Here’s how:
1. Make sure the clutch releases fully by shifting in
and out of reverse with the engine running and
with it stopped.
• If the shift effort is higher with the engine
running, the clutch is dragging. Repair it as
needed.
• If the shift effort is the same with the engine
running, go to step 2.
2. Park the vehicle outside, away from other cars,
and set the parking brake.
3. Raise the engine speed to 2,500 rpm.
4. Without pressing the clutch pedal, apply light
pressure to the shifter toward the gear that grinds.
The pressure should be the same as when you
engage the gear.
5. Hold the pressure for 5 seconds, then release the
shifter for 5 seconds. To avoid synchronizer
damage, follow these intervals exactly.
6. Repeat step 5 carefully 10 times.
7. Test-drive the vehicle. If it still grinds, you may
need to disassemble the trans, inspect it, and
replace worn or damaged parts.

 

SYnchros don't grind, the grinding your hearing is the dog tteth on the gear and the teeth on the slider..........onle the inner cone of the synchro is worn, it can't provide enough braking drag (really, it's only a brake!) to slow the gear down.

 

syncro mesh works great, but to really fix it you have to replace the parts like bense said.
i always run syncro mesh in my trannys. none of mine grind.
i had a ls tranny with a 3rd grind and syncro mesh got rid of the grind. however use the penzoil stuff not the gm. it cost less

 

bump for more opinions

 

I've done that procedure twice before. Both on customer cars, and both 99-00 Civic Si's. One time it worked, and the other time it didn't.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nomotor &raquo;</TD></TR><TR><TD CLASS="quote">ill report back in 15 min. i am going to try it on my ls tranny, 3rd grinds above 3200rmp</TD></TR></TABLE>

Thats a long 15 minutes.

 

hasn't anyone read about the "NEW" Acura fluid?????????

Just old school Pennz/GM Shitromesh fluid.

 

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

no.

cure = replace worn parts.</TD></TR></TABLE>

GM Synchromesh and Honda MTF don't fix trannies, they mask their issues (poorly) only sometimes.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by HT Chaplain &raquo;</TD></TR><TR><TD CLASS="quote">this should be in the tranny forum!! Oh wait </TD></TR></TABLE>

hahahaha.

Good info as always, Bense.

 

my 1990-91 si tranny is losing second and third, I need to know where to find parts to rebuild it? dont want to spend a fortune, but it is my daily driver for work, right now im skipping gears which inevitably will make it worse.

 

Honda dealer, only parts I'll use.

Define lossing 2nd and 3rd.........

A Rebuild?

I've done well over 150 trannys, never done a full rebuild.

 

Honda has retracted that Dec'99 service news bulletin and replaced it with a newer bulletin. The jist of is that you should not perform the synchro burnishing procedure on cars newer than the 1995 model year.

https://oncourse.iu.edu/access...s.pdf