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What diff oil should I buy?

Discussion in 'The Garage' started by Desert Rat, Aug 14, 2004.

  1. Desert Rat

    Desert Rat Fetch the comfy chair

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    Ok, did a search. Read all the tech articles I could find. They all just say "Then refill the diff with gear oil" never saying what weight or preference. Gotta get down to the store and pick me up some oil for the D60 front and Corp14ff rear. Question is, what to get? Preferences? Synthetic? Semi-synthetic? Can I run the same weight front and back? Back has Detroit Locker, front has ARB. Inquiring minds want to know. By the way, I do like synthetics generally speaking but for the break in period for two new rebuilt diffs?
     
  2. Hossbaby50

    Hossbaby50 3/4 ton status

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    I have always been told that you should break in diffs on standard oil, then switch to synthetic if you want to runs synth.

    I broke my 14bff in on 80W-140 for 500 miles. Then I switched to Redline heavy shockproof gear oil. I HIGHLY recommend this oil. It is expensive but it is awesome stuff. It is really thick. It helps reduce heat in the differential, basically eliminates metal to metal contact, and acts like a cushion between the gear teeth and all other metal surfaces. It acts like a 75W-250 weight oil /forums/images/graemlins/yikes.gif. It will cover all extremes of heat.

    It is like $10 a quart though, but if you just rebuilt a D60 & 14bff with all the good stuff then what is another $80 in gear oil. It is just a protection of your investment.

    If you want to run a more standard oil then I would run an 80W-140 synthetic after the break in period. I wouldn't run 80W-90 where I am at because of the heat. (AZ)

    Harley
     
  3. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

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    I am a fan of synthetic for the rear but for the front any gear oil is fine IMHO because the front diff doesn't get used hardly at all vs. the rear in a daily driver. You don't have to worry about the oil breaking down up front because the diff probably isn't spinning fast enough to generate a lot of heat anyway.
     
  4. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    90wt, but if you want to spend money on synthetic, use Redline. The PSI rating is so high that its almost like the R&P never touch. Good stuff! It would look really cool if you had a clear diff cover also! /forums/images/graemlins/histerical.gif
     
  5. surpip

    surpip 1 ton status

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    HIJACK /forums/images/graemlins/whistling.gif
    does the gov lock need lim slip additive?
    thanks,
    dale
    END HIJACK /forums/images/graemlins/peace.gif /forums/images/graemlins/waytogo.gif
     
  6. jon v

    jon v Registered Member

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    I use Lubrication Engineers Almasol geal oil #607 90w. It carries an 1100 newton shock load. Synthetics don't carry heavy loads in gear boxes. They are good for higher temps, like when pulling heavy 5th wheel trailers with low gear ratios, cause you generate higher temps then. For 4x4 wheeling the almasol 90w, or 140w is tops. I found it from professional trophy truck racers. You have to add friction modifier if you have a limited slip (ie eaton posi) /forums/images/graemlins/cool.gif /forums/images/graemlins/thumb.gif
     
  7. Desert Rat

    Desert Rat Fetch the comfy chair

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    I would think the synthetic up front would be a good idea too though especially since it doesn't see as much use. Doesn't synthetic remain more stable longer than regular petroleum stuff? I guess I'm going to throw in some regular 90 for the break in and then swap over to synthetic later.
     
  8. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

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    [ QUOTE ]
    HIJACK /forums/images/graemlins/whistling.gif
    does the gov lock need lim slip additive?
    thanks,
    dale
    END HIJACK /forums/images/graemlins/peace.gif /forums/images/graemlins/waytogo.gif

    [/ QUOTE ]

    yes
     
  9. Desert Rat

    Desert Rat Fetch the comfy chair

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    Well, went and bought a coupla gallons of the basic 90 weight stuff for the break in. I think it will be Redline or Mobil 1 after the break in is through.
     

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