Pages:
Actions
  • #1 by Attila on 30 Nov 2017
  • I’ve been off road plenty of times, but today, I forgot to disengage 4WD H when returning to the bitumen. I drove about 60km at highway speeds. Didn’t notice anything unusual. Could I have damaged anything?
  • #2 by Crackles on 30 Nov 2017
  • You could but unlikely. Seen it done numerous times without ill effect.
  • #3 by Attila on 01 Dec 2017
  • Oh cool. Thanks!! :)
  • #4 by Stepho_62 on 01 Dec 2017
  • Highly unlikley, chewed a bit more than normal off the outside edge of your front tyres is all.
  • #5 by GazLaz on 01 Dec 2017
  • You would know if you did!
    Straight driving is fine in 4h
  • #6 by dad on 02 Dec 2017
  • No worries Attila, that's what differentials are for. Check out how many 4WD cars get around let alone the Rally quicks.
    The sons mate in Canada runs his 4WD in H4 all through the winter. Most there do.

    Diff Lockers, however, are something you don't forget about.

    Cheers

    dad
  • #7 by GazLaz on 02 Dec 2017
  • Just dont turn tight unless the road is wet...you will feel the car feel sluggish when it starts to bind, make sure you stop and go into 2h straight away.
  • #8 by BirdmanFJ on 05 Dec 2017
  • Just dont turn tight unless the road is wet...you will feel the car feel sluggish when it starts to bind, make sure you stop and go into 2h straight away.
    Once it starts to bind, it would be quite hard to shift from 4H to 2H as there would be tension on the gears. You're better to turn the other way and unload the tension before shifting.
  • #9 by Lunchietey on 05 Dec 2017
  • No worries Attila, that's what differentials are for. Check out how many 4WD cars get around let alone the Rally quicks.
    The sons mate in Canada runs his 4WD in H4 all through the winter. Most there do.

    Diff Lockers, however, are something you don't forget about.

    Cheers

    dad

    There is a massive difference between 4wds like an FJ with a solid transfer case(no centre diff) and AWDs (or constant 4wd depending on which marketing Dept you listen to).

    An AWD or 4wd with an unlockable/lockable centre diff can drive all day in 4h. An FJ or any other part time 4wd with no centre diff can suffer massive damage and driving problems from drivetrain windup on grippy surfaces.

    The reason your son's mate does it in Canada is the slippery surfaces allow the drivetrain/tyres to slip enough if any windup occurs.

    If you still think it's ok, stick your FJ into H4 on clean bitumen in dry weather and drive in a circle. Enjoy the extremely loud banging from under your car...
  • #10 by GazLaz on 06 Dec 2017
  • Once it starts to bind, it would be quite hard to shift from 4H to 2H as there would be tension on the gears. You're better to turn the other way and unload the tension before shifting.
    Yes agree, good point.
    This wouldn't be obvious to the inexperienced.
  • #11 by Miles fj on 06 Dec 2017
  • There is a massive difference between 4wds like an FJ with a solid transfer case(no centre diff) and AWDs (or constant 4wd depending on which marketing Dept you listen to).

    An AWD or 4wd with an unlockable/lockable centre diff can drive all day in 4h. An FJ or any other part time 4wd with no centre diff can suffer massive damage and driving problems from drivetrain windup on grippy surfaces.

    The reason your son's mate does it in Canada is the slippery surfaces allow the drivetrain/tyres to slip enough if any windup occurs.

    If you still think it's ok, stick your FJ into H4 on clean bitumen in dry weather and drive in a circle. Enjoy the extremely loud banging from under your car...

    +1 from me on that one.
    Damages may also not be visible at the beginning but twisted shaft could happen....to snap at later/added stress
  • #12 by dad on 06 Dec 2017
  • Yes agree, good point.
    This wouldn't be obvious to the inexperienced.
    Wow I think I've learnt something Lads. I thought wind-up was a thing of the past. You may have jettisoned me into the 21st century. Well done.

    My 4WD early '70's experiences (training ;) was from my hard core Cousin and Brother all in tricked up FJ40's.
    Therefore I have NEVER run H4 or L4 on tar even on good gravel with any of my 4WD's as a result of great mentors, so I haven't experienced any issues with 4WD's or the FJ resultant wind-up as you claim.

    It's interesting that the Publican at William Creek advised not only correct Oodnadatta pressures but also advised leaving 4WD's in H4, wet or dry for the entire length of the Track.

    Cheers

    dad
  • #13 by Miles fj on 06 Dec 2017

  • It's interesting that the Publican at William Creek advised not only correct Oodnadatta pressures but also advised leaving 4WD's in H4, wet or dry for the entire length of the Track.

    Cheers

    dad
    This being a dirt track, it does make sense. The problem is more on the black top....for the FJ set up (no center diff)
  • #14 by RedFJC on 06 Dec 2017
  • I shift straight into H4 on gravel and get a much better driving experience, also doesn’t want to crab walk when hitting bumps etc.
  • #15 by Lunchietey on 06 Dec 2017
  • H4 is fine anywhere where the surface allows tyres to slip. Even a graded gravel/dirt/limestone road is fine as the surface allows any difference in rolling distances between tyres in a locked drivetrain to slip/slide/turn at a different speed.

    Ina dead straight line, all tyres rotate at the same speed, when you turn they all travel a different path and therefore turn at a different speed. In a 4wd like an FJ, the solid transfer case tries to force the front and rear wheels to turn at the same speed. On a grippy surface that is bad news, slippery surfaces it just means a slight slip of one or more tyres. Add in front and rear lockers and it's even worse.

    If you're driving straight across a patch of bitumen between 2 gravel tracks there's no need to go back to H2.
  • #16 by Crackles on 06 Dec 2017
  • Quote
    Lunchietey: An FJ or any other part time 4wd with no centre diff can suffer massive damage and driving problems from drivetrain windup on grippy surfaces.
    While theoretically there would be an increase in damage or premature wear from extended axle wind up, if you accidentally leave your car in 4H on the tar for 50 to 100 km you will generally not have any ongoing issues. I've done it a dozen times myself & the guys at work literally 100's of times over the years all without incident.
    Consider for a moment 4x4ing over in Moab where they are often in low range with lockers engaged on sheets of rock. We experienced continuous axle wind up for hours on end, the tyres chirping & squealing. Out of 100's of cars at Cruise Moab surprisingly not one had "massive damage" from axle wind up.

     DSC_0434.jpgForgot to disengage 4WD H when returning to bitumen
  • #17 by Lunchietey on 06 Dec 2017
  • Now turn sharply at high speed.

    Cvs can snap, diffs can break and premature wear is very likely. May not happen straight away. You may be lucky that the journey has been mostly straight etc or raining. Eventually damage will occur. If it didn't why the f**K does every single part time 4wd manufacturer including driveline parts manufacturers state very clearly not to do it and warns of damage if you do?

    Even rock is often quite slippery or smooth and seldom 'clean' or even flat(you're only using tyre edges etc) and often one or more wheels are slipping or able to slip. Driving in H4 on non slip surfaces(flat bitumen) is absolutely bad for your 4wd and absolutely can cause damage. Even while off-road when using lockers snapped CVs are common due to drive line shock when one wheel decides to do something the rest aren't.

    You also are not driving at high speed or over long distances when off-road. There will be regular chances for slip.

    Oh and I should add that I have experienced serious windup in a SWB Pajero a few years ago while driving a short distance between two tracks. I was passenger at the time and the chirp chirp chirp BANG was loud as hell. There is absolutely NO WAY that kind of mechanical shock is NOT hurting your drivetrain. No it didn't break on the day but exactly how many times would you want to risk your own car?

    I'm glad you haven't experienced any damage so far Crackles, but not every car(and tyre and surface) will be the same. I have even read about snapped CVs in road cars with locked rear diffs. A forgetful accident can't really be avoided but saying guys have done it 100's of times is negligence and dangerous to themselves (and potentially other road users)
  • #18 by Lunchietey on 06 Dec 2017
  • Straight form the FJ manual. Says pretty clearly that it can damage the FJ so don't do it(even if someone says they haven't damaged theirs… they are just lucky!)

    Also read this forum post. I count that as pretty serious damage...

  • #19 by Neil Watts on 06 Dec 2017
  • Uhmmm! I think the point is don't do it intentionally, when all is said and done there is some room for error.
Pages:
Actions