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SL500 R230 .. Differencial seems to Clunk on Full Lock -- When Cold.

Discussion in 'Engine, Drivetrain, Fuel and Exhaust' started by Dale Minton, Dec 2, 2012.

  1. Dale Minton

    Dale Minton Senior Member

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    Hi all, I've noticed for a time now that when I slowly reverse my SL from the driveway into the road whilst applying a reasonable amount of steering lock there appears to be a clunk or two from the rear end (although I can't feel it through the gearstick). I had put this down to the driveway being on a slight slope and the tyres grappling a bit as the two different levels of the drive and road met, as such I never really gave it too much thought. It's the same sort of subdued clunking I used to experience on a previous vehicle (of another make) and it was caused by the Limited Slip Diff plates grappling in the rear differential as the two rear wheels were rotating at different speeds when a reasonable amount of steering lock was applied. It certainly seems more pronounced in reverse than going forward but I've put this down to the fact that in reverse, and on lock, the difference in wheel speed would be more. Curiously enough, it doesn't seem to do this after the car has run for a few miles and some heat has got into the transmission (or maybe it's nothing to do with the transmission) - is it normal to experience something like this on an SL R230 when reversing on lock :confused: Advice please and thanks

    Dale.
     
    Last edited: Dec 2, 2012
  2. Mic

    Mic Senior Member

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    I do not think that is normal in so much as I have not 'clocked' such clunking when I reverse out of my drive on fullish lock.

    Mic
     
  3. alexanderfoti

    alexanderfoti MBO Forum Supporter Authorised Forum Supporter

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    Its not the handbrake shoes releasing is it?
     
  4. OP
    Dale Minton

    Dale Minton Senior Member

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    Mmmmmm, when the handbreak shoes knock off like you say it's pretty much instantanious, not after you've moved several yards, however, it is like something is sticking and then let's go, but sometimes it can do it more than once in quick succession --- weird, any further comments would be welcomed.
     
  5. alexanderfoti

    alexanderfoti MBO Forum Supporter Authorised Forum Supporter

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    Ah apologies, I did not realise it was after several yards, no idea then :)
     
  6. SL55 Mark

    SL55 Mark Senior Member

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    Thinking laterally, and applying landrover logic, propshaft, drive shafts, suspension ball joints, roof seals, wheel bearings, chassis flexing ... the list of possibilities is limited only by ones imagination.
     
  7. oigle

    oigle Senior Member

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    I would be quite inclined to blame the LSD - have seen a number of vehicles that clunk on hard lock. Strange that it would be worse when cold. A change of diff oil and be sure to use the correct LSD oil, might alleviate the issue.
     
  8. drmw

    drmw Moderator

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    it doesn't have an lsd - pity as it could do with one sometimes!

    I'd guess as simple backlash in the transmission drive train - nothing to bother about particularly, as you say, it goes away when it warms up.
     
    Last edited: Dec 4, 2012
  9. television

    television Always remembered RIP

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    There is nothing in the drive chain that could only make the clonk when cold, some SLs have the tendency to raise the rear end when reversing from cold and it could be a suspension noise, I would not worry about it at all.
     
  10. drmw

    drmw Moderator

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    You are probably right on the suspension being the cause.

    To expand on my thought process - as backlash is specifically set between the crownwheel and pinion teeth in the diff when it is built and as it will wear a little over time, this means when it is cold there is a bit more play than when new and when the diff is doing its job with each wheel rotating at different rates, then any play might become more evident
     
  11. television

    television Always remembered RIP

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    But any backlash in the diff is taken up as soon as R is selected, irrespective of any throttle applied
     

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