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What does reverse cut gears mean?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Eric M., May 18, 2002.

  1. Eric M.

    Eric M. 1/2 ton status

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    I always thought reverse cut gears refered to gears in a front dif. I recently saw an ad for a Dana 60 front without reverse cut gears. What does it mean??

    Thnaks,

    Eric M.
     
  2. m j

    m j 1/2 ton status

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    the pinion enters the dif above axle centre line
    with american trucks Ford seems to have started it
    for front applications it is stronger (read they can run smaller lighter stuff with equal strength)
     
  3. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Pinion above the center line of the carrier is called reverse cut or high pinion. The advantage is more lift with less drive shaft angle. Strenght is the same I would think. Strenght would have to do more with materials and casting of the housing. Should be pretty equal since the same forces are at work.
    I have heard of some concerns with lubrication on the pinion bearings on High pinion /reverse cut applications.
    On a standard rear axle the ring gear slings oil into the pinion bearing section. on a standard front the oil level is high enough that the bearings are in the oil. On a reverse cut neither is the bearings in the oil or is the ring gear getting oil slung into the bearings. The Pinion gear also has less oil contact. Even on a rear application since the pinion is on top it is interfering with the oil being slung into the bearings. They many times will have a slinger on the pinion that dips into the gear oil to get it up into the bearings but it's nowhere the volume that the ring gear would be moving.
    On a front axle that is probably not a big deal since it's only being used at low speeds. On a rear axle it could present a problem at high speeds. Lack of oil and cooling from the oil may result causing them to run hotter and wear faster.
     
  4. m j

    m j 1/2 ton status

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    no the strength is not the same
    a normal cut dif in a front application is driving the coast side of the gears
    on a rev cut it is driving the correct side
    the oiling is made to work and there are thousands of these in service
     
  5. morphed86k10

    morphed86k10 1/2 ton status

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    Yeah, MJ hit it on the head. The reverse cut gears, when used on a front axle, are driving on the side meant to handle the most torque (when driving forwards of course). Standard type front ends are powering on the coast side of the gears when driving forward. Reverse cut should be a little stronger in the forward direction. Mostly it doesn't matter unless you need the higher pinion for driveshaft angles, or you have lots of horsepower and huge tires and have 35 spline stub shafts. Otherwise the stubs (or hubs or even U-joints) usually let go before the ring gear does.
     
  6. Leadfoot

    Leadfoot 1/2 ton status Premium Member

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    MJ is correct but so is Grim. The Axles themselves are the same strength (or close enough that it doesn't matter), and the gears are the same strength (tensile and hardness), but MJ is correct in stating that a normal front end drives the reverse side of the gear when going forward whereas a reverse cut rides on the drive side while going forward. High torque on the coast side has been known to chip/break teeth, but not because the gear is weaker, it's because the design of the teeth weren't meant to carry the load on that side. So both are correct, but as grim stated the reverse cut front axle is better on driveline axles, and as MJ stated it's better from a torque input strength on a front axle. It's stronger/better suited for the application (front axle), but isn't inherently stronger.......If that makes any sense whatsoever. /forums/images/icons/crazy.gif
     

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