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P38A torque converter lockup

Discussion in 'Range Rover' started by kermit_rr, Mar 7, 2020.

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  1. kermit_rr

    kermit_rr Well-Known Member

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    Hi
    Never really noticed before, so not sure if it's normal or the beginning of the end!
    Particularly noticeable today, didn't get lockup until I'd done a couple of miles and the engine was warm, irrespective of the speed i was doing.
    Normally, it'll lock anywhere from 35-40mph and up depending on conditions
    What's normal on these?
    Cheers
     
  2. Datatek

    Datatek Well-Known Member

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    Lock up in 4th gear normally happens at around 50 mph and around 40/45 in 3rd depending on throttle opening. If yours is locking at 35-40 it's not normal.
     
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  3. wammers

    wammers STILL BREATHING. Donater

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    In D high range torque lock occurs at around 50 MPH after this speed has been maintained for a minute or so, it will drop out of torque lock when the speed has reduced to below 35 MPH for a minute or so. The engine operates at reduced power until the engine and gearbox have reached working temperature.
     
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  4. Henry_b

    Henry_b SPARES OR REPAIR

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    Mine used to lockup at 45 and stay there until 20mph, usually requiring me to change down manually..

    Changing the fluid a few times, helped it significantly..
     
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  5. kermit_rr

    kermit_rr Well-Known Member

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    Maybe it is actually at 40 (in 3rd) and then I'm dropping back down a bit, is a bit hard to keep an eye on the speedo while driving.
     
  6. kermit_rr

    kermit_rr Well-Known Member

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    If it's at reduced power for a while that would explain it i think
    I shall keep calm and carry on!
    It tends to snatch 2nd gear when changing up on a light throttle, but nice and smooth with a bit more pedal, but at 125000 miles on the clock i don't expect perfection. In guessing it's the original box
    Changed the oil and filter when i got the car, oil was dark but didn't look 'bad'
     
  7. wammers

    wammers STILL BREATHING. Donater

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    If it's snatching second gear the valve block is sticking, get yourself a bottle of Lucas. Snake oil that actually works.
     
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  8. Datatek

    Datatek Well-Known Member

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    Lucas Transmission fix with a second oil change might help. Only about half the oil comes out when you change it, so a second and maybe a third change after at about 1K mile intervals can be beneficial.
     
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  9. kermit_rr

    kermit_rr Well-Known Member

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    Do i just leave that stuff permanently? Or oil change after x miles?
    When i did the oil change, i bypassed the oil cooler and let it pump until it started to come thru a bit cleaner. Ran out of fluid at that point
     
  10. kermit_rr

    kermit_rr Well-Known Member

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    Next silly question, assume i suck a bottle full of oil out of the box, then pour the comments of the 'fix' into the box job done?
     
  11. Henry_b

    Henry_b SPARES OR REPAIR

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    you substitute a litre of ATF for the lucas.

    4.2 litres whould drain from the sump..
     
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  12. kermit_rr

    kermit_rr Well-Known Member

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    Cheers. If i recall i got thru around 2 bottles, don't remember if they were 4 , 4.5 or 5L. Just made sure it was up to the level afterwards
     
  13. dubbleRR

    dubbleRR Well-Known Member

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    The green sensor on the head ,can affect how long it takes to change gear ,,On mine the gearbox held the gear for longer got better as it warmed up ,changed the green one and it was fine again ;), ...RR
     
  14. wammers

    wammers STILL BREATHING. Donater

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    Correct, the green sensor is the engine ECU sensor so any lag in that would give problems.
     
  15. RangeRoller dt

    RangeRoller dt Well-Sprung Member

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    He has a 4.0v8
     
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  16. wammers

    wammers STILL BREATHING. Donater

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    I was answering dubbleRR who does have a diesel. Also 4.0 L petrol and diesel are the same box.
     
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  17. RangeRoller dt

    RangeRoller dt Well-Sprung Member

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    Is always worth changing green sensor on diesel.
     
  18. kermit_rr

    kermit_rr Well-Known Member

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    Thought the green one was no longer available? Or am i thinking of something else
     
  19. RangeRoller dt

    RangeRoller dt Well-Sprung Member

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    They are all available, blue can be tricky to source not silly money, is V8 not different sensors?
    I have spare new brown (no aircon) if anyone needs one.
     
  20. wammers

    wammers STILL BREATHING. Donater

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    The ECU restricts fuel availability at low temps for emission purposes. So engine power is limited until working temp is achieved and a clean burn is possible..
     
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