Diff's

nominousnominous familEE
in Engine & Drivetrain
I've been looking into the differences between the diff in the 4WD L3 box and other Honda diffs.
Unfortunately in th Shuttle box it's a 12 bolt ring gear.
Honda don't do this in any other D or B series Honda with one notable exception.

I've also been trawling through the JDM EPC and looking at the JDM models and cannot find any mention of a LSD in the front, but certainly in the back, where it is also a 12 bolt ring gear.
Now we know that the rear diff in the normal rear casing can be changed for a FWD unequal length shaft LSD diff. So is the RTi rear LSD diff the same size as the front shafts or the same as the normal smaller ones in the rear?

What bugs me about the front LSD or lack of in the JDM EPC for the shuttle/beagle, is that for the CRX SiR it got a factory optional LSD kit.
This is mentioned in the EPC, so why not for the Shuttle?

The CRX diff consists of a LSD Ring gear and LSD as, you guessed it, it's actually 12 bolts.
I'm going to try and track down one in the UK to borrow and see if it fits, but has anyone tried this??


Another interesting gem I turned up is that the Honda HR-V which is a D series SOHC with 4WD option is actually using CR-V running gear, AND the tranny. So much so that the bell housing is a different part number (duh...) but the rest of the casing and bolts on's including the Diff and ring gears is the same as the CR-V casing. Same part numbers. The gearing is different, but the internals would swap between the boxes.

Here's my search results if you're interested:

http://www.hondaoriginalparts.com
Not the greatest website to use as they seem to use different part numbering format, but the good things is that they match across the different models.
List of some diffs:

PFKL578996 16v CRX/Civic EDM
PFKL578909 VT CRX/Civic EDM
PFKL576193 HRV 4WD EDM

PFKL578909 LS Integra USDM
PFKL577222 ITR (B18C5 - Torsen LSD) EDM

PFKL576249 Civic VTi (B16) EDM
PFKL576248 Civic ESi (D16Z6) EDM

PFKL576193 CRV 4WD EDM

PFKL578903 Civic EF 4WD EDM
PFKL578903 Shuttle 4WD EDM

41200-PY1-020 JDM CRX SiR LSD option. Ring gear and Diff and bolts. Not seperate parts.


Shuttle uses a 12 bolt diff. All the others above are ten bolts.
The JDM CRX / Civic with factory LSD uses a 12 bolt diff as an exception
There were after market 12bolt plate diffs, I've seen people with them fitted on CRX-UK.



CRV Diff
http://www.hondaoriginalparts.com/honda ... k_03=18810
CRV Transfer
http://www.hondaoriginalparts.com/honda ... k_03=18810


HRV Diff
http://www.hondaoriginalparts.com/honda ... k_03=19279
HRV Transfer
http://www.hondaoriginalparts.com/honda ... k_03=19279

CR-V and HR-V seem to share the same drivetrain as you can see from above.
The gearbox casing is the same too.
The outer side is the same part number, but the bell housing is different.
The internal shaft layouts are the same but the gearing is different.
Rear diffs all have the same part numbers too.
So essentially a CR-V drivetrain but for D series engines!!

Comments

  • JakerJaker familEE
    Wagon RT4WD USDM rear diff is not 12 bolt. It is 10 bolts just like the USDM FWD diffs. This would have been a huge stumbling block for me if that were the case. It would have made the diff install much much more involved. The difference here between the RT4WD front diff and the regular FWD diff is as you already mentioned, 12 bolts versus 10 bolts, but also the RT has blind holes whereas the FWD diffs are threaded for the ring gear bolts.
  • nominousnominous familEE
    Yeah. Sorry if that didn't come through properly in the post. But that's what I found.
    It's the Intrac which uses 12 bolts in the rear, the rest is 10 bolts in the rear.
  • SiWagonSiWagon Council Member
    Check with Haydz.He claims the 90+ 4WD had a front LSD .
  • JakerJaker familEE
    I have the front diff out of one of my transmissions with the ring gears removed. Again, the front diff has blind holes, just like the rear diff, and it's the small ring gear (the one that sends power to the transfer case) that is threaded. The bolts themselves are quite a bit longer as well, and are... get this... right hand thread as they go in from the opposite side of the diff. I think the 1st hurdle here will be to be able to find someone to weld shut 8 of the 10 holes on a FWD LSD, and then drill 10 new holes to line up with the ring gear bolt holes on the RT4WD ring gears. Then it will be necessary to drill out the threads on the remaining 2 holes to allow the bolts to pass through into the ring gear unhindered.

    But before we go that far, we should look at the spacing of the ring gear flanges, and the carrier bearing seats to see if the offsets align to place the ring gears correctly in relation to the carrier bearings and the transmission housing.

    This 1st step could be done with any FWD D series diff, open or LSD. I'm sure some of you have a diff laying around that we could work with.
  • SiWagonSiWagon Council Member
    :shock: Here's my thoughts.

    Jaker's right the rear diff is 10 bolt.2 reasons:1)some1 here fitted a 2WD LSD into the rear diff.See this link (+++SiWagon FYI: '88-91('96)JDM Wagon Options & PARTS.)under LSD:
    http://www.civicwagon.com/showthread.php?427-SiWagon-FYI-88-91(-96)JDM-Wagon-Options-amp-PARTS
    2)This might be the confusing part.The JDM EPC shows a 12 bolt ring,but only list the number of required bolts as 10.Was this a picture error or number error? :?

    The 4WD front diff is a 12 bolt ring.The CRX(mentioned by nominous) and 2WD are only 10bolt.This includes CRX 16 ESI,VTi & VT.

    Haydz mentions a frt 4WD LSD,but nominous & I couldn't find one.
  • JakerJaker familEE
    As mentioned above by Nominous, the CRX EF9 came with an optional LSD which had 12 bolts on the ring gear. That's a B series, but as I investigate the construction of the RT4WD USDM transmission further, I'm seeing things that make me think the internals are more B series like than D series (larger bearings, larger gears/synchros, etc)...

    I am the one that installed a FWD LSD into the rear pumpkin (diff housing) on the USDM RT4WD. I put an OBX diff from a 92-00 Civic D series in. All it took was to bore out the threaded ring gear bolt holes to blind holes, as the rear diff ring gear is threaded for the ring gear bolts as opposed to the diff being threaded.

    Nonimous,

    What would a used 5 speed HR-V transmission cost? Can you post up the gear ratios from that transmission (I'm mostly interested in 1st, 2nd and the final drive)?
  • nominousnominous familEE
    Sorry, been away for ages.
    Probably get a HRV tranny for about $300 or less on a good day.
    I have a feeling I posted those ratios, not 100% sure tho.
  • nominousnominous familEE
    Jaker wrote: »
    I have the front diff out of one of my transmissions with the ring gears removed.

    Do you still have that handy please ?
  • ragenasianragenasian Moderator
    Jaker parted his ride and gear out awhile ago.
  • nominousnominous familEE
    Bummer :(
    Was a source of inspiration!
Sign In or Register to comment.

© Vanilla Keystone Theme 2025