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Professional DIY Diff And Auto Trans Breather

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  • Professional DIY Diff And Auto Trans Breather

    Hi There i recently completed the difficult task of creating a home made diff and auto trans breather that is as professional as bought kit. I have provided pics as attachments as i don't know how to put them in post. I'm hoping this will help others that have had the same issue i had of creating one from scratch. I imagine it would be same for new pajeros.

    What You Will Need
    • 7 metres of vacuum hose with 4mm hole - I purchased from Repco for $3.50 a metre.
    • 1.2 metres of oil resistant hose with 6mm hole - I purchase from a hose place for $17 a metre.
    • 6 mm hose to hose joiner and 6mm t-piece joiner - $3 each from Super Cheap Auto.
    • 3 x 4mm t-piece joiners - 50c each from hardware store, they are used for irrigation.
    • Fuel filter with 6mm connections- $4 Super Cheap Auto.
    • Flat mould aluminum - $3.90 Bunnings.
    • Cable Ties and hose clamps.

    1. Run 4mm hose from rear diff to the top of auto trans along break line pipe that is on drivers side of fuel tank and carefully cable tie without crushing hose.
    2. Unplug 4mm hose from top of auto trans this is the centre diff breather line. Install 4mm t-piece joiner into end of this line and 4mm hose from rear diff.
    3. Install a 1.2 metre piece of 4mm hose to remaining connection on 4mm t-piece joiner. Run 1.2 metre of 4mm hose into engine bay under the abs relay. Ensure this is run between firewall and heat shield as displayed in one of the pics.
    4. Unplug 6mm hose from top of the auto trans and install 6mm hose to hose joiner. slide hose clamp over and clamp hose to joiner. install 1.2 metre piece of 6mm hose to other end and clamp. Run hose into engine bay running the same line as the 4mm hose.
    5. In engine bay install 4mm t-piece joiner into 4mm hose. there is a little rubber cap on a pipe just under the air box on the fire wall side. this is front diff breather. run 4mm hose from this to 4mm t-piece joiner. this may require heating hose or putting slits in hose as the end of pipe is flared. See photo.
    6. Take fuel filter and install 8cms of 6mm hose to the top side that has lip. Install 6mm t-piece joiner to other end of hose.
    7. On on side of 6mm t-piece joiner file of ribs to allow 4mm hose to fit on.
    8. Install 6mm hose from trans to ribbed side of 6mm t-piece joiner and 4mm hose from t-piece joiner in engine bay to filed end. once again may require heating of cutting slits.
    9. To create bracket take flat mould aluminum and place in vice get clamped to round object the same diametre of fuel filter. bend aluminum around round object till complete circle is made. you may need to use vice and crush at certain spots without round object in centre to get tight fit. once tight fit is achieved cut aluminium leaving a 5cm tab. Drill hole in tab for mounting bolt.
    10. Install bracket in engine bay near abs relay. there is a threaded hole here i believe it is 6mm metric.
    11. Install fuel filter into bracket.
    12. You can blow in bottom of fuel filter to check it is air tight.

    The fact the filter is upside down prevents it filling with water when hosing in engine bay. Also in the rare case oil travels all the way up hoses it cant contaminate trans fluid. I linked the Front, Rear, Centre diff using t-piece joiners so there was only one fitting onto fuel filter instead of three. Also they all use same type of oil so there is no issue with cross contamination.

    I hope with the information provided and photos others it is easy enough for others to follow. Please let me know if you need more help or like my design. Once again sorry i could not put photos in post.
    Attached Files
    2015 Automatic PC Challenger with TJM bullbar and underbody protection

  • #2
    Hi Michael,

    First up great writeup! I did this one ages ago but instead of using Vac hose I used (of all things) hospital grade oxygen tubing, yours looks alot neater than mine does simply because its all 4mm diameter the whole way along and its all one color, mine however is in some parts green and in other parts foggy clear looking.

    One question I do have, how did you get to the transmission breather, I have tried and tried and tried and I simply cannot get to it, my hands are just too big to get a grip on it and when I think i do have it, its either a plug or cable, could you tell me roughly how far along the breather hole is so I can finally get to and do mine?


    05 NP GLX 3.8 Auto. 2" Lovell/Bilstein Lift, ARB Deluxe Winch Bar, Granke mk3 12,000lbs winch, Uniden UH015sx, HID spotties, Roof mounted light bar, Work lights, Upgraded stereo, Tinting, 2.5t tow, dual battery setup (homemade), Radar Renegade tyres, wired up dummy lights, Bushskinz Sump/Intercooler plates, home-made diff breathers (front and back) and a cheap ebay snorkel.

    brake upgrade, oil seals (again!!)


    • #3
      Marc, not wanting to hijack his thread but i did this 2 weeks ago also.

      The auto breather is almost at the top of the bellhousing, held by a small bracket on the RH side 10mm bolt from memory. Hold's both the AT and TC breather, just uncliped it from the bracket and shoved a brass joiner into them - I ran them seperate.

      2004 NP Did, 2.5 inch Hi Flow cat and centre muffler, Kings 40mm Springs/Oztec Struts, Browns Intercooler Guard, Custom 3mm Sump &Transmission Guard, Great Kumho KL78 245/75 A/T's & 235/85 Hankook Muds. Red Arc Dual Battery Isolator, Narva 225 Ultima, Extended Diff's and Tranny breathers, DIY Sliders & Proud.


      • #4
        I think it's a good idea to run the T/FER and AUTO breathers separate just in case the auto trans boils over from overheating or over filling that way you wont contaminate the t/fer with auto oil
        05 NP Platinum 3.2 DID Mods yet to come
        Other ride 07 BF Ghia