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The ZF 6HP26 Service Procedure.

Discussion in 'Technical Archive' started by Henry_b, Feb 10, 2019.

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  1. Henry_b

    Henry_b Well-Known Member

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    1) If For any reason a Mechie has to do this Service Make sure he does the procedure to the letter.

    2) Also If he fills it with normal Dextron ATF Your Gearbox will be permanently Damaged.

    Unlike most of the Transmissions used in the FFRR's the 6HP26 is a very good unit.
    However as with anything it needs maintenance.

    it has been known to happily cope with 700nm of torque and over 600hp with proper maintenance
    It's used in the
    2006-2010 L322 Range Rover
    2???-2??? Range Rover Sport ;)
    Land Rover Discovery 3-4 :)



    LR Jaguar and indeed anyone who uses this Transmission states it's "Filled for Life"

    Which i'm sure you all know is a load of crap, this transmission requires a service every 60k to maintain reliability and longevity.

    OIL..

    There is always an argument regarding the fluid this transmission requires.

    I'ts ZF LIFEGARD 6 a service kit will cost around £240 and contain.

    Many argue that any fluid meeting shell m1375.4 is compatible, but as with everything oil quality varies depending on manufacturer, and TBH the OE route is cheaper than a new gearbox because of inferior fluid,

    1 A New Oil pan, it's also the filter!
    2 New oil fill plug
    3 21 t40 bolts for the sump
    4 New Tcm adaptor seal.
    5 7-8 litres of Lifegard 6.

    Many manufacturers state they make alternative kits for half the price, IMO it isnt worth it.

    PROCEDURE..

    1 Remove Oil Filler Plug (T50)
    2) Remove Oil Drain Plug and Replace Plug after all transmission oil runs out.

    3) Remove all 21 T27 or T40s depending on whether its previously been serviced from around the pan and drop it, inspect the magnets inside for any debris

    4) Loosen and remove the TCM connector from the back of the gearbox, remove the seal and replace with new one, + Not to be confused with the one that sits under the Valvebody.

    4.5 Remove the Valvebody and replace the Megatronix seal, If you want too ;)

    5) Install the new Oil pan and torque the pan bolts to 10nm in the correct "pattern" to ensure it doesn't warp!
    [​IMG]

    5 Having loosened the fill plug first "T50" add in fluid till it flows out of the hole initial fill is around 3-4 litres

    6) The transmission fluid temperature must be between 30°C and 35°C before checking can begin. use an infrared thermal gun aimed at the bottom of the pan

    7) The vehicle must be level with engine running at idle speed.

    8) Step on the brakes firmly, apply parking brake and shift to P R N D waiting for 3 seconds in each gear.

    9) With the engine running at idle speed and the selector in Park position, remove the filler plug. And Monitor the transmission temperature, at 40°C, add fluid 'till it flows out the fill

    10) If no oil runs out when the filler plug is removed, the fluid level is too low and oil needs to be added
    until it overflows.

    11) With engine running, install the oil filler plug and tighten to proper torque. 25nm.

    Now it goes without saying, don't turn the engine off and then add the fill plug as the fluid from the converter and oil cooler will flow back and **** out the filler hole, you have been warned. ;)
    4-6 litres added to the sump denotes a correct fluid change.



    Here are a few videos.





    The ZF Transmission will leak out of the 1) the sump and 2) the TCM adaptor seal. After a period of time, this often goes unnoticed and causes the fluid to run low and ultimately ruin the box.
    This is probably the No1 reason for 6hp failure,
    that and abuse ;)

    It's worth checking an potential purchase to make sure it doesn't leak.


    LURCHES.

    This is a common fault caused by an electrical gremlin that tends to fault some 6HP26 gearboxes.

    Type 1 Lurch: The gearbox kicks into a lower gear (usually gently) as it changes down through the gears when you are gradually slowing down, foot off the accelerator, usually without braking.

    Type 2 Lurch: As you accelerate, the gearbox seems to hesitate in neutral for a split second, the Engine revs a bit, and then the gearbox slams into gear with a sharp hard jerk, and the car leaps forward, like when you drop the clutch at 2000+ revs in a manual car. Usually this happens as you accelerate from a slow roll, for example when you slow down at a roundabout or traffic lights but don't need to stop, then you accelerate hard.


    Both of these can be fixed with a re-flash of the gearbox ECU this is around £60 depending on the place.

    Another less common/rare cause for the above is a broken valvebody to gearbox seal..

    This one, its worth replacing this when you're servicing it, so do it!

    it's easy you just drop the valvebody and its right there, 10min job, on top of the time for a service of course ;)
    https://www.googleadservices.com/pa...hUKEwjb6uXJ86_gAhW56KYKHZ-aCuYQ9aACCD8&adurl=

    It sits under the Valvebody and as the name suggests seals the valvebody to the gearbox, if this breaks the pressure drops it'll cause the above, and also a slur between gear changes and a delay when changing gears D-R for example will take a few seconds..


    This is a topic I will add too as i go on but for now it is complete

    Thankyou..


    @blue beasty

    Would you please add this to the technical section please..

    H
     
    Last edited: Feb 21, 2019
    Big Fuz and gstuart like this.
  2. Henry_b

    Henry_b Well-Known Member

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    This is what a standard ZF service kit looks like,

    [​IMG]

    Add to it this seal..

    [​IMG]

    It sits under the Valvebody..

    [​IMG]

    Its to the left of this pic.

    ignore the circle ;)

    Worth doing this while you have the sump off.

    proactive maintenance and all that.. ;)
     
    emcm0034 and gstuart like this.
  3. Henry_b

    Henry_b Well-Known Member

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    Just to Add.

    Do not add any kind of additive, friction modifier or pixie **** to this transmission.

    The Lifegard fluid has a specific chemical makeup that must be maintained, if this is screwed around with, in any way gearbox damage will occur..

    And TBH if you're contemplating adding any of the above your g'box is probably already had it.
     
  4. Big Fuz

    Big Fuz Member

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    Update. I got a mobile mechanic out to look at topping the oil up which he did. Unfortunately it only held 1 litre before black waste starting flowing out of it. So it's not low or dry. The black coloured fluid does cause concern though. Tried gear again and although a little quieter, still the same result. More pronounced now though is the Park selection as it sounds like cogs racheting before clunking into park. It's now on the back of a recovery truck on the way to the indy. I await diagnoses when they get a chance to look at it. apparently could be a day or 2 as they're busy. Will keep you updated. Thanks again all.
     
  5. Henry_b

    Henry_b Well-Known Member

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    He did use the correct oil didn't he?

    Considering the black shít that came out and the fact it was very low, and the noises internally i'd budget for a rebuid, or a new recon unit.
     
  6. Mark Piercy

    Mark Piercy Well-Known Member

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    nice one enry!
     
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