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Super select problems - any help will be appreciated

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  • Super select problems - any help will be appreciated

    Hi guys,
    Pajero 2001, 3.2 diesel, GLS, A/T
    I'm having unsolved issues with the super select system.
    At the beginning of a drive (the car is still "cold") I can change from 2H to 4H pretty easily (usually 1st or 2nd try),
    Changing from 4H into 4HL starts to be problematic but after 2-3-4 times It will engage.
    Changing back from 4HL into 4H is hard... and also leaving 4H into 2H.

    BUT,
    After driving 4X4... (lets say from 15 minutes to hours), leaving 4HL mode is pretty much impossible
    I can try it tens of time, adding a forward or reverse drive, engaging it again and trying to get out of it ... NOTHING works.

    I checked for oil in the transfer, added some and it did not help,
    changed all of the vacuum lines in the front and the two solenoids. it helped engaging 4H more easily but was not suppose to help the 4HL (correct?)

    Since it can engage 4H when the car is 'cold' i assume the actuator is OK ... (once again, correct?)

    What else can cause this?

    Thanks

  • #2
    For the car to go into 2WD, you need vacuum in the actuators. Since the engine is running, you must have vacuum, so it seems that vacuum or lack thereof is not a problem. I think the problem comes from the transmission trying to lock up. This comes from the tyre size. If one or more tyres is either a different brand or different size, the rolling radius can be different and this can cause the actuator to hang up when you try to go back into 2WD. A simple way to check this is to stop on a hard surface and reverse the car, turning the front wheels slightly. Since the front wheels will travel slightly further than the rears, forward travel winds up the transfer case and reversing will unwind it. If this cures the problem, the cause can be tyre size or simply lack of usage of the actuator. You can then go onto a gravel surface and shift into and out of 4 WD and if it is caused by lack of usage (quite a common problem), regular exercising of the system will free it up.

    Comment


    • #3
      Originally posted by erad View Post
      ..... I think the problem comes from the transmission trying to lock up. This comes from the tyre size.
      All tires are the same. unless a 4psi deferent between than is an issue - I would overrule this option.

      Originally posted by erad View Post
      ...... A simple way to check this is to stop on a hard surface and reverse the car, turning the front wheels slightly. Since the front wheels will travel slightly further than the rears, forward travel winds up the transfer case and reversing will unwind it..
      When I tried to get out of 4HL yesterday I did it with wheels straight forward, and as mentioned - it did not work.
      However, having to drive like that back home (not more than 2KM) on asphalt road, with turns, I did stop a couple more time and try to get out of 4HL, still - no luck (these times not with reverse..)

      Can it shad some light ?


      Comment


      • #4
        You may have a switch on your transfer case that is on its way out.

        It's very easy to think of an electrical switch as either conducting or not conducting, as that's what they're intended to do. We think of them as short circuit (a closed switch) or open circuit (an open switch).

        When connected to an ecu of some kind, the electronics are actually checking the resistance of the circuit - it's either high resistance (open) or low resistance (closed). Because the circuit has wires and connectors in it, the low resistance threshold to indicate a closed circuit isn't zero - the ecu accepts a non-zero resistance as a closed switch.

        If you have a switch that has less than perfect electrical contacts then its resistance in the "closed" position can be close to the ecu's limit for what it considers to be closed. When the transfer case is cold and resistance is low, everything works as expected. As the transfer case heats up, the resistance of the switch may also be increasing, to the point that the ecu no longer recognises the switch as closed.

        As I understand the system (but could be wrong) when you move your selector lever from 4HLc to 4H the actuator will move the internal mechanisms, and look for certain switches to change state. If it doesn't see the expected switches change then it flags an error and stops trying to drive the actuator. If you then try to change from 4H to 2H the ecu still has its error flag, and won't attempt to drive the actuator - it thinks the actuator didn't work properly for the previous change, and it won't attempt to drive it any further.

        When your car is cold it can see the switches change, and everything works as expected. When your car is hot the system doesn't "see" the switches change to 4H (when changing from 4HLc), so it generates an error code.

        A potential work-around for you to try:

        In my experience, if you select the transfer case mode you want when everything is turned off, the actuator will drive in the appropriate direction without checking the switches for the intermediate positions. If you're in 4HLc and your transfer indicates errors when you try to select 4H, stop and turn everything off. Select 2H (and Neutral), then restart your Paj and see what happens - the actuator should drive all the way to the 2H position regardless of what the switches indicate.

        Similarly, if you're in dire straits off-road and can't switch through the various modes, turn everything off, select 4HLc (and Neutral), then restart. The actuator should drive all the way to the 4LLc position regardless of what the switches indicate.
        NT Platinum. DiD Auto with 265/70R17 ST Maxx, Lift, Lockers, Lockup Mate, Low range reduction, LRA Aux tank, bull bar, winch, lots of touring stuff. Flappy paddles. MMCS is gone!

        Project: NJ SWB. 285/75R16 ST Maxx, 2" OME suspension, 2" body lift, ARB 110, 120l tank, bullbar, scratches, no major dents. Fully engineered in SA. NW DiD & auto in place - a long way to go....

        Scorpro Explorer Box

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        • #5
          "When I tried to get out of 4HL yesterday I did it with wheels straight forward, and as mentioned - it did not work.
          However, having to drive like that back home (not more than 2KM) on asphalt road, with turns, I did stop a couple more time and try to get out of 4HL, still - no luck (these times not with reverse..)

          Can it shad some light ?"

          When I suggest to try reversing, I meant reversing whilst turning the steering wheel, This way, the front wheels will travel further than the rears, and thereby unwind the transmission if it has been wound up when driving forward. On my NW (with different tyres front & back)_I used to have troubles shifting from 2WD to 4WD and the other way. The center diff light would come on and all other lights would go out after about 25 km if I drove in 4WD whilst towing my caravan. If I stopped the engine, all would be good for another 15 km and the lights would go mad. After replacing the front tyres with ATs (the same as the rears), this problem went away and I have towed the caravan thousands of km since then with no flashing light problems. I could not visually detect any significant difference in the rolling radius of the new vs old tyres, and it must have been a marginal difference because it took a long time to show the problem. When I read the codes for the transmission, there were 2 codes relating to different tyre sizes.

          Your problem may not be the same as mine, but it is worth trying the reversing trick and if it goes away, this gives a clue as to where to look. I doubt that it is the switches in your case because they work when it is cold but not when it is hot. So you have vacuum being applied to the actuator, and if the actuator was sticking, I expect that it would stick more when it was cold rather than hot.

          Comment


          • #6
            Originally posted by nj swb View Post
            You may have a switch on your transfer case that is on its way out..........
            Hi nj swb,
            I doubt if switchs are the issue here:
            1st of all, I replaced all 5 sensors on the transfer with new ones and the problem stayed the same. (chances I had a faulty one then and same faulty one now is highly unlickly...)
            2nd, When the ECU detects "an error" it gives a clear sign of it - leaving inly the center lock lamp blinking.
            This is not the case here. It keeps the other whells' lights in their right status.
            3rd, I can feel when the car is in 4HL, and that is the case of it. the actuator really does not move back and get released. it is in 4HL.

            Gil

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