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Hybrid Transmission: Anything to do missing?

Discussion in 'General Tech and Maintenance' started by BlueCrxNC, Mar 29, 2004.

  1. BlueCrxNC

    BlueCrxNC VTEC CRX

    Likes Received:
    Jan 21, 2004
    I currently have a 1989 Honda CRX HF (1839 lbs) with a JDM D15B Vtec (128 hp). At the time of the swap (a few months ago) I was unable to obtain a Si tranny. Just last week I started to hear the whirring and chattering of bearings going out (Input Shaft bearing and probably a few others) Time for a new transmission as the HF tranny isn't worth the $200-$300 worth of new bearings and seals.

    This weekend I purchased a ZC tranny (20 spline = 1989-91) which has the closest gearing of any D-Series transmission. I personally don't wish to use the equal-length axles that are required by the ZC transmission... So I'll be swapping in my HF's differential so that I may continue to use the stock axles. (the HF, DX and Si Differential are all the same right? Minus the Ring Gear and bearing sizes)

    While I have the new tranny broken down, I'll install the HF 5th gear (including the corrosponding counter gear) so that I may keep my highway speed RPM's down (making my long drives much more pleasant)

    Just thought I'd share my plans with everyone and see if I'm missing anything that needs to be done in order to carry my plans out.


    Running 185/60/14 (22.74 Inch) Tire/Wheel Combo

    My Hybrid Transmission

    ZC 1-4 (1st: 3.250; 2nd: 1.944; 3rd: 1.346; 4th: 1.033)
    HF 5 (5th: 0.694)
    ZC Final Drive (Final: 3.88 )

    Data shown with redlining @ 7200rpm

    1st: 0 - 38.64 (idle - 7200)
    2nd: 38.64 - 64.60 (4306 - 7200)
    3rd: 64.60 - 93.31 (4985 - 7200)
    4th: 93.31 - 121.58 (5526 - 7200)
    5th: 121.58 - 180.96 (4837 - 7200)

    5th @ 80mph: 3183 rpm
    ZC 5th Gear @ 80mph would be 4027 rpm!


    Things to do:

    --Replace all bearings and seals
    -There's a difference in the bearing sizes
    Countershaft bearing (30x47x21 = HF; 30x55x21 = Si)
    Mainshaft bearing (6205UC/26 = HF; 6305SPL = Si)
    Differential Oil Seal (35x56x8 = HF; 40x56x8 = Si)
    Speedometer Drive Gears have different part numbers between HF and Si
    The transmission cases are of course different part numbers because the bearings are different sizes.

    Since the only sizing that is different is one dimension, can I use either size bearings on the HF differential?
    If I can use either size bearing on the HF Differential and ZC Main/Countershafts then I can use either case (ZC or HF) I want right? Just pick the bearings that match the casing?

    --Swap in HF 5th gear and counter gear

    --Swap in the HF Differential
    -I am required to re-shim the differential upon bearing replacement right?
    -Since I'm using the ZC Countershaft (part of Final Drive) I need to swap on the ZC ring gear onto the HF Differential correct? Is that all that the "final gear" consists of?

    I've been searching every Honda/Acura website I can find as well as Google etc to gather as much info as I can. The above questions still remained somewhat unanswered to me from what I've found.

    Thanks you for any help you may give.
    John (BlueCrxNC)
  2. cws13

    cws13 Senior Member

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    Nov 15, 2002
    By the time you go through all of this you could buy an Si trans for the same price
  3. cheese9988

    cheese9988 Senior Member VIP

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    Apr 25, 2003
    Lowell, MA
    I found an si in the junkyard, guy sold me the tranny, linkage and flywheel for $200.
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