General tranny info covering all models & motors.
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By teal_dx
#67284 So your tranny grinds into 3rd gear, as many of them do. This is usually the first to wear out. You can buy another used transmission, but who knows how long it will be before something goes wrong with that one. I chose to fix the problem in my 93 si transmission instead of buying another one, even though the price would have been about the same (for the 3rd/4th gear synchro set), plus a few extra hours of my time.

Rebuilding a countershaft or mainshaft is not very complicated. You just have to be careful and pay attention. It is a lot like building a huge sandwich... you have your bottom bun, ham, salami, cheese, lettuce, tomato, pickes, mayo, top bun. Those things must go in a certain order. The countershaft must be pot together exactly as it was or you'll have big problems. You'll need a clean work area with enough space to lay each part out in the order you removed it. Then all you have to do is pick up each one in order and put it on the mainshaft, just like building a big heavy metal sandwich. When installing the new parts, a thin coat of oil should be applied, don't put them on the mainshaft dry. Also don't drop anything on the floor. Very tight tolerances and precise teeth make this work. it could be easy to damage these parts, so pick a good work space to start because you don't want to move everything once you start taking it apart.

This thread is just to help you get familiar with the parts & assembly of the mainshaft. Before doing this yourself, have a manual in front of you. By reading on, you agree that I am not responsible for any damage you do to your vehicle.

First I'm going to take it apart.

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First you'll need to remove the large ball bearing on the end. Mine pulled right off without tools, but you may need a bearing puller.

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You'll need a puller similar to the one shown above. There's larger bearing pullers that will also work. They put the pressure over a larger area vs 3 points like the one I rented from autozone. So if you are using the type I am, be very careful not to let it slip and damage any teeth on your gears.


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notice I put an old nut between the point where the threaded bolt at the center of the puller contacts the mainshaft. This is to keep the pressure from damaging the shaft itself.


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Now the parts have been loosened with the puller, they can be removed.

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First remove the 5th gear synchro sleeve.... (already on table) and the next piece I'm looking at removing is the 5th gear synchro hub.

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Now I removed the 5th gear synchro hub which the sleeve slides on/over. The gold piece we're looking at next is the 5th gear synchro.

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Remove the synchro (synchro spring is attached to it) and now we're looking at 5th gear.
Last edited by teal_dx on Tue Sep 02, 2008 3:13 pm, edited 2 times in total.
User avatar
By teal_dx
#68034 Image
Pull off 5th gear (on table) and you'll see the needle bearing that sat inide of it.

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Pull off the needle bearing and you'll se the colar that the needle bearing sat on.

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the collar will slide up freely. in this pic you can see that 4th gear is next, and it also has a needle bearing on the other side of the collar. Be sure to watch how things are coming apart so you know how they go back together.

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I've removed the collar and now 4th gear & the 4th gear needle bearing are moving freely since there is no collar under the needle bearing.

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I pulled 4th gear off to reveal the needle bearing flopping around on the mainshaft, since the collar is not there.

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Needle bearing is removed and the 3rd/4th synchro set is next to come off.


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The 3rd/4th synchro (and spring attached) has been removed. This is actually the synchro on the 4th gear side of the hub. There will be another synchro on the 3rd gear side. (Honda only sells the synchros as an entire gear set.) Now I'm ready to pull the sleeve.

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3rd/4th synchro sleeve has been removed and I'm looking at the 3rd/4th synchro hub next.

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Slide the 3rd/4th synchro hub off just like you did on the 5th gear synchro hub.

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Here is the 3/4th syncho on the 3rd gear side of the hub.

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with the 3rd gear synchro removed, you're looking at 3rd gear next.
User avatar
By teal_dx
#68039 Image
with 3rd gear removed, you're left with the needle bearing that 3rd gear rides on.

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And here the 3rd gear needle bearing is off and you can see the entire mainshaft dissassemled.



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I had a 3rd gear grind, here is the replacement gear set from Honda. (all I really needed was the hub sleeve as you'll see below.)

OLD vs. NEW 3rd gear:
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Looking for rounded teeth, there isn't really much wear.


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New 3rd

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Old 3rd

New 3rd/4th synchro hub/sleeve vs. Old one:
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I'm holding the new one.

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Old hub is on the left... again, not much wear.

3rd/4th synchro sleeve (old is on the left):
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A closer look at the old one... notice the rounded teeth.

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and the nice sharp teeth on the new one.

There's the problem.
User avatar
By teal_dx
#68040 Now let's have a look at the synchros.... Old on left, New on right:
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old

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new

So the old ones really were in pretty good shape. The new synchros come with new springs (they are more like rings) as well.

Next swap out all of the old parts in your lineup with the new replacement parts. (3rd, 3rd synchro, 3/4 hub & sleeve)

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And your old parts will become come very expensive / cool looking paper weights 8)


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Now you're ready for re-assembly.

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3rd gear needle bearing is installed.

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Slide your new 3rd gear over the nedle bearing, in the direction shown.

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Synchro slides on the tapered end of 3rd gear, in the direction shown.

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Then the 3rd/4th synchro hub. The new one may fit a little tighter.

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I put the mainshaft upside down in a drill press. (for an even surface) From there it can be tapped in with a mallet, or I pushed it in with the drill press (turned off of course). It is not a really tight fit, a hydraulic shop press is not needed.


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Next the 3rd/4th synchro sleeve is installed over the hub. It will only do on a certain way. Notice in the 4th pic above, there are some U shaped grooves on the hub. The correct teeth on the sleeve need to go into these U shaped grooves, or else the sleeve will not go on all the way. Even if you have it lined up and it is not going on, rotate the short teeth to the next U groove and try it that way. There is only ONE way these will go on, even though it looks like any of the 3 short teeth will line up with the U grooves. Don't force the sleeve on and screw up your new parts.
User avatar
By teal_dx
#68046 Image
Next install the 4th gear synchro. The flat edge must be facing up to 4th gear.

Image$th gear needle bearing...

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4th Gear, tapered edge does down toward the synchro. The gear & needle bearing will be loose because the collar is not in yet.

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Here is how the collar goes in (4th gear removed just to show) But it must be installed after 4th gear since 4th will not fit over the collar center.

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So center the loose 4th gear & needle bearing on the mainshaft.

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And put the collar between the needle bearing & mainshaft.

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Then 5th gear needle bearing on the other side of the collar.

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And 5th Gear as shown with tapered side facing up.

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Here I have put the 5th gear synchro on, larger flat side facing 5th. And have the synchro hub ready to go on.

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The synchro hub needs to be pressed on. This is why you had to use a puller in the beginning.



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It is not too tight of a fit, a hydraulic shop press is not needed. My metal table saw table has grooves in it that are good for holding the hub & mainshaft as shown. Then tapping (hard) it with a mallet + all of the weight of the entire mainshaft on the hub will help to press it on. (The dia. of the drill press was too large for the 5th hub.)

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With the hub pressed on, you're ready for the hub sleeve. Again, this only goes on one way. Don't force it.

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Then the ball bearing and you're done!

Assuming you did this in a clean work area as you should have, put the completed mainshaft in a bag until you're ready to put the tranny back together.

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User avatar
By vtec veezy
#69598 nice write up Teal, as usual! but yeah, that looks pretty hard, especially if you dont have all the specific tools, so i'm gonna have to go the expensive route and take it in to a transmission place :cry:
User avatar
By smokinsoljah420
#86111 Thread ressurection! How much did that 3rd/4th kit cost ya? :( My third gear is shot! Also how much do you charge an hour lol! Cause i dont got the tools or the brian-power lol!!!
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By teal_dx
#86137 http://www.hondaautomotiveparts.com/aut ... UNTERSHAFT

http://www.hondaautomotiveparts.com/aut ... +MAINSHAFT

There's price lists for the parts on both the mainshaft & countershaft. Majestic is usually a lot cheaper than your local dealership too. All those parts are for a 93 Si, the car my tranny came from. Dx/Lx and Cx or VX might be different.
After the cost of shipping, you might be better off getting it rebuilt locally. But after learning on my own tranny, I could do it again in a lot less time.
By TurboHatch
#87862 how was the fork? Its worth mentioning that 9 times outa 10 in a honda tranny like ours a 3rd gear grind is more often from a worn or broken fork and not so much from syncros like every one is so fast to blame, that or like you found a worn sleeve, and some times a bearing can walk up out of the case, even more so in the 88 to 91 cable trannys where the forks are crap white metal. forks are super easy to swap you dont have to press anything on or off. moral of the story is its super rare for the actual syncros in our trannys to require replacement.
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By sabdagr8
#243543 I used this d.I.y to help me rebuild me tranny good info man
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By rehan01
#273488 Hey teal or any1 that would like to answer my question.

so for awhile now my cars been popping out of 5th gear and i've been thinking that its prolly because my shift linkage is so damn loose.( i'm thinking its because the bearing under the shifter is just worn out and the bushing at the transmission, if im not mistaken)

thats problem one, now today i tried to go into 4th gear and it wudn't engage. what exactly would you guys recommend me doing, and what parts should i buy? thanks and the help would be greatful :D
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By teal_dx
#273571 Check your clutch fluid first- top off if low. Does the pedal feel squishy? you may have air in the system.
I'd definitely replace the sloppy shift linkage bushings before trying to troubleshoot any shifting problems.
Can you put it into 4th without the engine running? If so, it's a clutch engagement problem.
User avatar
By OmarG
#275433 I recently had a problem with my 5th gear popping out. As it turns out, I lost a LOT of transmission fluid (axle popped out partially) and so all it needed was to be topped off. (and for me to pop the axle back in.)
By wolfman93
#331201 Teal roughly what it cost you? I have a 96-00 ex tranny that's the main shaft has quite a but of slop in it.