Civic/7th Gen Project - Fix third gear crunch EP3 Civic Type-R gearbox

Discussion in 'Project & Modification Logs' started by SpeedyGee, Thursday 27th Dec, 2012.

  1. SpeedyGee Administrator Staff Team

    England Speedy Birmingham
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    Decided to pull apart a Civic Type-R gearbox that has a third gear crunch.

    Ok, so here we go, first make you have a clean work area. Also clean the outside of the gearbox so you don't drop any dirt into the gearbox as you shaking the case about trying to take it off. Place the gearbox on some wooden pieces so that its not sat on the input shaft.

    2012-12-26 10.49.11.
    Can start dismantling now ... first up is the gear change mechanism, held in by 4 bolts and then just wriggles out once the sealant lets go.
    2012-12-26 10.56.41.
    Remove the seal bolt that is on the side of the gearbox (using a drain bolt socket)
    2012-12-26 11.11.04. This reveals a locking spring clip/snap ring, this holds on to bearing at the end of counter shaft.
    The spring clip needs to be opened up and pushed out of the bearing groove, later on we will need to push the bearing down.
    2012-12-26 11.11.51. Next up is the removal of the spring loaded ball bearings which sit in the grooves of the fork rods.
    2012-12-26 11.01.00.

    As always I always miss a few crucial photo taking moments. Here we've missed the housing being taken off.
    This just needed all the bolts removing from around the housing and then a fair amount of wriggling to free the bearings at the end of the counter shaft and the input shaft to free themselves from the housing.

    2012-12-26 16.36.25.
    Also missed taking pics of the diff being removed, this needed a hub puller to free it.
    So what you can see in the pic below is the diff, next to the diff the three change forks, about the diff the input shaft, above the change forks the counter shaft and then the little cog on its own is the reverse gear.

    2012-12-26 16.36.02.
    In the picture below you can see that the input shaft has been disassembled and parts laid out in order.
    Needed a hub puller to get the right most gears off (6th gear), the rest just slid off.

    2012-12-26 16.54.54.
    So in more detail, bottom row, input shaft itself, to the right of this the third gear sprocket (I left the roller bearings inside the gears)

    Next row up third gear synchro (but no ring), hub, slider, fourth gear synchro with ring, fourth gear and finally the fifth gear.

    Top row, fifth gear synchro and ring, hub, slider, 6th gear synchro and ring, sixth gear and finally bearing.

    2012-12-26 16.54.48.
    All the parts look in good nick, synchros have fairly sharp teeth, hubs and sliders are all good, no damage or excessive wear. Same goes for all the gears.

    So... why was third gear crunching ? Well have a look at the the pic below. Its the ring for the third gear synchro. It was sat in pieces at the bottom of the housing. It's beens totally shattered. The job of the rings on the synchros is to catch the gear as the slider come towards them and stop the gear from spinning, making for an easy engagement. Without the ring your trying to engage a moving gear hence the crunch.

    Theres a magnet at the bottom of the gearbox housing, this is where most of the broken parts had collected, this would have made for good viewing and again I forgot to take a picture of that :-(

    2012-12-26 17.31.45.
    Below you can see we have cleaned up the gearbox housing ready for reassembly

    2012-12-26 17.36.44.
     
    Last edited: Thursday 27th Dec, 2012
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  2. Ichiban Founder Staff Team

    England CJ Leeds
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  3. SpeedyGee Administrator Staff Team

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    Cheers dude, I'll be commencing reassembly in the next couple of days .. watch this space :Smile:
     
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  4. Doc Expert Advisor ★ ★ ★ ★ ★

    Matt Peterborough
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    Great thread. A gearbox is one of the few things I haven't stripped yet. Would love to have a go and understand properly how they work. :GoodJob:
     
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  5. SpeedyGee Administrator Staff Team

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    The principle is very simple Doc. Hmm let me go grab some pics and I'll try and explain.

    - - - Updated - - -

    Actually I'm going to cheat and let this video show you how a synchromesh gearbox works



    If you take one apart it all starts to make sense anyway :Smile:
     
    Last edited by a moderator: Saturday 22nd Feb, 2014
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  6. Doc Expert Advisor ★ ★ ★ ★ ★

    Matt Peterborough
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    Cheers for that, it's very interesting. Syncro's are very clever in their design but very simple mechanically. I'd like to take one apart to see it 1st hand how they work, as you say it'll make more sense that way.
     
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  7. SpeedyGee Administrator Staff Team

    England Speedy Birmingham
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    I've swapped out the youtube video with a more informative one.
    - - - Updated - - -
    Another informative video from the same youtube user

     
    Last edited by a moderator: Saturday 22nd Feb, 2014
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  8. SpeedyGee Administrator Staff Team

    England Speedy Birmingham
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    OK here we go, let's commence reassembly.

    First up install the diff, this needs pressing in gently until the lower bearing is seated. All contacting surfaces are lubed up.

    2012-12-28 17.30.14.




















    Main/input shaft assembly :-
    2012-12-28 17.35.07.




















    Third gear pushed onto shaft
    2012-12-28 17.35.29.




















    Third gear synchro
    2012-12-28 17.36.12.




















    3rd and 4th gear hub and slider, taking careful not of orientation of both hub and the slider
    2012-12-28 17.37.23.




















    Fourth gear synchro
    2012-12-28 17.37.52.




















    Fourth gear pushed on
    2012-12-28 17.39.41.




















    Close up view of everything so far, so 3rd and 4th are complete.
    2012-12-28 17.39.21.
     
    Last edited: Wednesday 9th Jan, 2013
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  9. 93 ACCORD Club Member ★ ☆ ☆ ☆ ☆

    This is some committed work, hope it yields a nice 3rd gear back, for those VTEC 3rd gear pulls!
     
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  10. SpeedyGee Administrator Staff Team

    England Speedy Birmingham
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    Ok so moving onto 5th and 6th gear.

    5th gear plus 5th gear synchro pushed on
    2012-12-28 17.40.01. 2012-12-28 17.40.49.




















    Next up is the hub for 5th and 6th gear, this needs tapping on, you need to watch the gap between the 3rd gear and the gear on the shaft. Check spec for correct spacing.
    2012-12-28 17.42.34. 2012-12-28 17.42.36.





















    With the hub on, the slider/sleeve and 6th gear synchro can go on
    2012-12-28 17.44.43. 2012-12-28 17.45.38. 2012-12-28 17.45.26.




















    6th gear dropped on, followed by mainshaft bearing.
    2012-12-28 17.46.38. 2012-12-28 17.47.34.




















    And here we have it, complete mainshaft. Give a full inspection and final measure up.
    Also check that the sliders can freely move between gears (don't forget to add some oil so they can slide nicely).
    2012-12-28 17.47.48.
















    You needs more than two hands to drop the main shaft, countershaft and forks all into locations.
    Basically hold the countershaft and main shaft together and get someone to insert the shift forks.
    When all three shift forks are slotted into their sliders, drop everything together into location.
    2012-12-28 19.00.23.




















    Line up the shift forks so they are in neutral
    2012-12-28 19.00.32.




















    I'm missing a couple of pictures, basically the next steps are drop in the reverse gear and bolt down the forks.

    Once all that is done, your ready to slowly bring the housing down, tapping all the way round. Not forgetting the locking snap ring at the end of the countershaft. This needs fully opening whilst the housing is being tapped down. Once the housing is fully on, lock the snap ring.

    2012-12-28 20.59.39.
     
    Last edited: Thursday 10th Jan, 2013
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  11. SpeedyGee Administrator Staff Team

    England Speedy Birmingham
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    Gearbox is in the car.

    Took the car for a test drive, man that is one smooth gearbox now, all gears go in super smooth. No more crunching.
    Makes VTECing a real pleasure :vtec: :OTT:

    Job done !!!
     
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  12. Ichiban Founder Staff Team

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    I will be down for a spin .