Getting a truck home with a bad differential

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by DMAX66, Oct 18, 2018.

  1. Rideandrepair

    Rideandrepair Road Train Member

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    Not really
     
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  3. AModelCat

    AModelCat Road Train Member

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    Heat = work. Watch your axle temps when pulling a hard grade. Bet the temps are pretty even. If only one axle did the work, only one axle would get hot.
     
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  4. Rideandrepair

    Rideandrepair Road Train Member

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    I’ve often wondered why tires on rear wear more and summed it up to tire scrub especially on longer wheelbase. Then became convinced it was from Drive and torque.Could it be both? Under normal operations maybe the rear axle has less weight therefore causing to drive more? I’ve noticed the right rear tire Especially and r/r spring bushing wears more. That must just be from torque.The tire scrub theory seems would apply more when front axle was driving during normal highway use. I always thought that the r/r was doing more driving due to the extra wear yet in order for r/r to have more scrub wear the left rear would have to be doing more driving. Since power seems to go to the lighter wheel the torque idea doesn’t work.The axles aren’t limited slip or “posi” right? I just wonder exactly what contributes most to the right rear tire and bushings always wear more.
     
  5. AModelCat

    AModelCat Road Train Member

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    My guess is since most air ride suspensions don't equalize weight like walking beams do, more weight is on the forward drive axle because the 5th wheel is often slightly ahead of centre. That would make it easier for the rear axle to slide and scrub tires.
     
    Last edited: Oct 19, 2018
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  6. DMAX66

    DMAX66 Light Load Member

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    So if I pulled the axles on the rear I would have to have the power divider locked in order for the truck to move?
     
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  7. swaan

    swaan Road Train Member

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    Yes.
     
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  8. swaan

    swaan Road Train Member

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    I contribute the wear on right rear tires to the road system . The crown of the road and how we are always on the right hand side. Left hand turns vs right hand turns ect ect ,......
    Same applies to the steer tires. Why is it that majority the time the drivers steer will wear faster then passenger???
    Same theory applies.

    Nothing to do with drive torque or very very little but everything to do with scrub
     
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  9. Oldironfan

    Oldironfan Road Train Member

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    I've watched axle temps on hot day pulling in mountains.
    And the front diff is hot on those days 220 degrees about. The rear will sit at no more than 150 degrees.
    My trans being manual will get 230 degrees about. I'm guess the trans cooler is liquid, not air cooled. Stupidest engineering ever on this 579.
     
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  10. AModelCat

    AModelCat Road Train Member

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    I think what confuses a lot of people is that it looks like the driveline goes straight through the front housing (which it does) and that locking in the power divider engages the front drive axle pinion. In reality both pinion gears are driven and the power divider lock just locks out the differential action of the power divider gears.
     
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  11. tommymonza

    tommymonza Road Train Member

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    Twice a week my truck gets stuck in the yard because I back the rear drives up on the pad that is there for trailer landing gear.

    Backs up fine and dandy. Next morning go to leave and the front drives are spinning in the air from the soil settling
     
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