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2006 Durmax Transmission Cooling Lines Leaking

Discussion in 'Mechanic and Repair' started by ed2hess, Jan 20, 2018.

  1. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,752

    I have looked at repairs shown on utube and it looks nasty. I also seen the repairs showing cutting and flaring 3/8" line and using rubber line with 2 hose clamps? Has anybody tried that?

    Views are up from ground.......spongy looking stuff is dirt


    I can't see where these two lines going up make the turn towards the radiator....:cry:


    I would need some slack to get flaring tool on.
    Last edited: Jan 20, 2018
  2. bmc1025

    bmc1025 LawnSite Senior Member
    Messages: 528

    Use a tubing cutter and cut out all the rubber sections (cut the hardline) and take them to a hydro shop. Have them make some assemblies the same size with compression fittings on the ends to attach to the original hard line. Even if you buy new complete lines from GM they will eventually leak especially in cold weather.
    hort101 likes this.
  3. bmc1025

    bmc1025 LawnSite Senior Member
    Messages: 528

    Don't be afraid of their compression fittings they are rated over 2500psi. Your trans cooler lines see about 60 psi max depending on temperature.
  4. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,752

    At least three ways to go. 1. cut and flare lines and use rubber hoses with hose clamp. 2.get three replacement lines 3. Get threerubber lines and new connectors from Alligator.

    This kit runs close to $300 looks like lines easy to route but have to put new fittings on cooler radiator and trans....Unscrewing them could be tricky especially ones on radiator

    Screenshot (131).png

    Parts this way around $100....looks like routing them could be night mare.

    Screenshot (135).png

    Cost of this probably $50...might be challenge getting enough room for flare tool..does seem simplest

    Screenshot (136).png

    Anybody do this one?
    Last edited: Jan 21, 2018
  5. RussellB

    RussellB LawnSite Fanatic
    Messages: 8,968

    I'm scared to work on my diesels. I had a shop replace my fuel (low pressure leaking but replaced both) and transmission (just because it was already in the shop) lines on my 04 duramax. Wasn't cheap but I sure felt better. Good luck
  6. bmc1025

    bmc1025 LawnSite Senior Member
    Messages: 528

    The kit Alligator kit is the best way if you do not want to spend time at the hydraulic shop finding the fittings and possibly having to order them.

    The long line that you have pictured can be done relatively easy, I pull them out the slot in the front bumper. If you are not very mobile having someone to help guide it all the way back is helpful.

    Once you take out the passenger fender liner and front splash plate there is a lot more room.
    hort101 and ed2hess like this.
  7. bmc1025

    bmc1025 LawnSite Senior Member
    Messages: 528

    I would not do the flare and clamp. While these are not high pressure, they are very high flow and when cold and high idle the restriction from the coolers causes much higher pressures than normal.
    Remember this is a 5K Allison transmission not a 2K installed 4l80E.
    hort101 and ed2hess like this.
  8. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,752

    Local auto zone kind of parts stories can't seem to find part numbers for the three lines I need. Guess my truck has allison transmission chev don't give any reference in their books? Any way has anybody bought these lines from chev? Guess I will begin pulling wheel wells, front etc off to determine if I can replace. Alligator might be best option but I hate messing with removing/replacing fittings on radiator.

    Screenshot (138).png

    I keep forgetting what goes where in my mind.
  9. bmc1025

    bmc1025 LawnSite Senior Member
    Messages: 528

    Lower 20835123 (front port to bottom radiator)
    Upper 20835125 (longest line from rear trans port to AUX cooler)
    AUX 20835127 (AUX cooler to upper radiator port)

    They are cheep on amazon
    Last edited: Jan 24, 2018
    hort101 likes this.
  10. ed2hess

    ed2hess LawnSite Fanatic
    Messages: 14,752

    Thanks a lot .....I am going to give it a try
    bmc1025 likes this.

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