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Swap chronicles: Transmission, gear swap, LSD, clutch and flywheel

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    Swap chronicles: Transmission, gear swap, LSD, clutch and flywheel

    Work in Progress.

    10/14/2013. UPDATE: The tranny, clutch and flywheel are in! Holy shit balls! Even though I still cant go crazy with it, because of the break in period. It feels fucking awesome! Smooth clean shifts, definitely more aggressive and f22 5th gear fuel economy.

    The measurements table has been updated, one more video has been added and took a few pics with my phone when the camcorder battery died. At a later date I'll record the reassembly of my donor tranny.

    If there's anything you think I should add to this thread please let me know.



    Rebuilt M2S4 (H23) transmission
    H2A5 (F22) 5th gear set from spare H2A5 (F22) transmission
    Mfactory LSD - part# MF-TRS-05H22
    Competition Clutch - 11.5 lbs Flywheel
    Competition Clutch - Clutch 1.5 part# 8014-1500

    Additional supporting parts

    New Honda Final Drive bolts - part # 90017-689-000
    MFactory magnetic drain plugs for tranny and oil pan - part# MF-ENG-02SET
    TASAuto Stainless steel clutch line - part# 191300
    ARP Flywheel bolts - part# 208-2802
    ARP Clutch pressure plate bolts - part# 108-2201
    NTN differential tapered bearings - large and small
    Torco MTF


    Like many of you I've been wanting to do this swap for a while now, but finding definitive detailed info is hard to come by. From my many hours of research, I know that many have done the swap successfully but most fail to give any real useful data. I did find some useful threads but even many of those threads would die incomplete or the OP would fail to add the additional data promised.

    As you may know the goal of the H23 tranny and the 5th gear swap is to upgrade to the more aggressive 1-4 gearing of the m2s4 (H23) transmission and retain the freeway friendly 5th gear of the F22.

    Iíve R&R one transmission before but never gotten into the guts of one until now. I've researched different DIYs on many forums and YouTube videos. Both covering F, H, B and D series transmissions. The plan is to have a video camera running nearly the whole time. Not for a DIY but more for others to review my work. But I'm feeling pretty confident I can to do this. So this may end up becoming a DIY or a what not to do post.

    I will be posting Youtube videos as I progress and I imagine I'll be stopping many times to ask for advice.

    Originally I was planning to use an OBX LSD. But, because of build quality issues written about on way too many forums, I decided to go with the MFactory LSD instead. I did find some articles and a website that have upgrade/rebuild parts for the OBX LSD that resolve many of the build issues. The same site does a good job of explaning the flaws and has a good "How To" guide to repair the flaws. See below.


    List of Youtube videos and forum posts I used for reference.
    Many more links to come...

    How Does a Manual Transmission Work? -EricTheCarGuy

    Evans Tuning Differential Swap Tech Article - Part 1-3
    (Doesnt cover the gear swap but these videos pretty much cover everything else. Even though this is meant for a B-series tranny it helped me a lot.)

    Prelude f/h22 transmission R&R - Part 1-3

    Civic Clutch and flywheel Install


    Prelude Service manual PDF download
    Last edited by Tishock; 11-20-2015, 09:59 PM.


    1) Counter shaft 5th gear. The m2s4 5th gear has oil notches/valleys on both sides. While the h2a5 only has them on the bottom side and not the top (See pics). Should I add the oil notches/valleys or do I need to get them done professionally? I'm assuming it does matter, or does it?

    UPDATE: You do have to add the oil pasages



    2) So it looks like I’m going to need a 2mm shim/washer between the countershaft 5th gear and the bearings. ID will need to be 25mm and the OD will need to be at least 35mm. See pics for gear height difference. Any suggestions on what I should use? What material should it be made of? I was thinking of using an old bearing from my spare f22 tranny and having it machined to size.

    UPDATE: I ordered a shim, # 8 25x35x2 from This should take care of my spacing issue.

    H23 .................................................. ............... F22 - Splines do not show through the top of the gear

    Spacing between H23 gear and bearing

    Spacing between F22 gear and bearing



    1) The diff wobble is not normal in video #5 @ 8:15 minute mark . I placed the h2a5 diff in to the m2s4 case and there was considerably less wobble. But still some wobble. The h2a5 diff in its own case had very little if any wobble. The m2s4 diff in the h2a5 case had some wobble but not nearly as much as it did in its own case.

    - Not happy about this . The large outer ring race was not seatedt/level in the diff housing. Also the corresponding large bearing was not completely seated on the diff. Fortunately I'm using new bearings and of course a new LSD so this will be fixed.

    UPDATE: using new bearings and the matching races did correct this issue.

    2) My h23 tranny was missing the stopper ring (see pic). When it was rebuilt it must have been left out. Yeah I was right these sons of bitches that rebuilt the tranny did not re-install the Stopper Ring (see pic) under the bearing on the main shaft.

    UPDATE: Fortunately the h2a5 (f22) Stopper Ring fits the m2s4 (h23) mainshaft perfectly.

    Last edited by Tishock; 09-27-2013, 03:26 PM.



      These measurements were taken using a cheap HF digital caliper so dont expect these to be dead on. But they should be close enough.

      UPDATE: More measurements taken and some pics added/replaced.

      1st measurement

      2nd measurement

      3rd measurement

      4th measurement (top)

      5th measurement (bottom)

      6th measurement (bottom)

      7th measurement (bottom)

      8th measurement (top)

      9th measurement (top)

      Last edited by Tishock; 10-08-2013, 02:33 AM.



        I'm just going to upload the video clips unedited. I'll try to add some details above each video as I go. So far its just following the service manual. If this does become a DIY I'll add the pages from the service manual and maybe re-shoot some of the clips

        Rebuilt M2S4

        __________________________________________________ ________

        __________________________________________________ ________

        __________________________________________________ ________

        __________________________________________________ ________

        Video #5 - See Issues in post #2 - Diff should not wobble like that @ 8:15 minute mark

        __________________________________________________ ________

        __________________________________________________ ________

        __________________________________________________ ________

        __________________________________________________ ________

        __________________________________________________ ________

        __________________________________________________ ________

        I did record myself doing this part but Evans Tuning's video is so detailed that there is no point in me uploading my version. This is exactly what I did except we torque our FD bolts to 74lbs. Make sure to use new bearings on your new LSD.

        I got on a groove and forgot to turn the camera on when replacing the new matching races. Its not a terribly difficult process you just have to be careful to tap them in straight. Using a bearing driver set makes it easier.

        __________________________________________________ ________

        m2s4 (h23) tranny with h2a5 (f22) 5th gear set installed. The shift forks were not installed for this test fit.

        __________________________________________________ ________

        Just for shits and giggles.

        h2a5 (f22) tranny with m2s4 (h23) 5th gear set installed. The shift forks were not installed for this test fit.

        __________________________________________________ ________

        Last edited by Tishock; 10-08-2013, 04:51 AM.


          I'm just going to use this as a place holder for pics being used throughout this thread.

          h23 with f22 5th gear set

          f22 with h23 5th gear set

          The following pics are courtesy of H311RA151N

          Last edited by Tishock; 06-08-2015, 10:36 PM.


            My observations and hopefully helpful tips for others.
            Last edited by Tishock; 09-09-2013, 02:19 PM.


              Did you measure the thickness of the 5th gears? I have read that the F22 5th gear is a bit wider than the H22 5th gear and it needs to be shaved in order to install it in an H22 transmission.


                See updated post #4.
                Last edited by Tishock; 09-16-2013, 02:06 PM.


                  I love what you are doing here. Details, pics, videos. Everything being measured correctly.

                  You are the man

                  Quality stuff in your thread here!
                  Originally posted by wed3k
                  im a douchebag to people and i don't even own a lambo. whats your point? we, douchbags, come in all sorts of shapes and colours.


                    Thank you sir.

                    I'm trying my best to keep things organized. And I still have a lot more to add to this.
                    Last edited by Tishock; 09-05-2013, 10:35 PM.


                      Lots of respect and wonder at how much devotion this takes. Rebuilding the transmission is an accomplishment in itself, let alone upgrading and revolutionizing it like you are, well, my regards. I have a feeling this will lead many people to start doing what you have done.. Thanks for all your hard work. It's much appreciated.
                      Originally posted by Quashish

                      noobs be like where to be buying hella flush yo?



                        Yeah, the reason why I bought a spare f22 tranny and a rebuilt h23 tranny. Was so that I could take my time to do this project. The more I tinker with the guts of these 2 trannys, the more everything is making sense to me. The manual does a pretty good job of breaking everything down but outline images of parts only help so much. Seeing the parts in real life, makes it a lot easier to understand. I hope to share what I learned with the rest of you with these videos and photos.

                        Now, I'm still a long way from having everything installed but I'm feeling really good so far.


                        Again, If there's anything any of you think I should add to this thread please let me know and I will do my best to get it done. Also, I will be adding a couple more questions and many of my notes/observations to this thread throughout the week. So stay tuned.

                        Last edited by Tishock; 09-16-2013, 02:07 PM.


                          Subscribed , Big props on taking this on, cant wait to see the finished product.

                          Sold too: Grumpys93, '93CB7Ex, Bunta, prodh22accord, SSMAccord, fleetw00d


                            Reminds me of when I had to change the 5th gear needle bearing on my H2A5 a couple years back. Except you're actually taking measurements and video; awesome!

                            Originally posted by tishock View Post
                            Again, If there's anything any of you think I should add to this thread please let me know and I will do my best to get it done. Also, I will be adding a couple more questions and many of my notes/observations to this thread throughout the week. So stay tuned.
                            Since you have the measurements, I would have to say that there is one measurement missing: you should take a measurement of an "outside diameter" (the gear part) face to its opposing "inside diameter" (the hub part) face, so that you know the offsets from both sides.

                            You only need one of the two, e or d, and you can calculate the rest. Having both wouldn't really hurt anything though.
                            Last edited by reklipz; 09-12-2013, 02:40 AM.



                              I'll get those measurements and post them over the weekend.