Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Gov Locks - use Friction modifier or straight gear oil?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by kpanza, May 7, 2002.

  1. kpanza

    kpanza 1/2 ton status

    Joined:
    Dec 8, 2000
    Posts:
    1,579
    Likes Received:
    0
    Location:
    Lake Forest, Orange County, California
    Quick question - we were going to change the fluid in my brother's rear 14bsf with factory Gov-Lock and I can't remember if the GovLocks use any friction modifier or not? Is it just straight 80-90W gear oil, or do you also add in some limited slip additive or anything??

    Thanks
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,978
    Likes Received:
    189
    Location:
    Roy WA
    You are going to hear different opinions on this. GM says no (its in the service manual scans on my site) but others have done so.

    I guess one way to look at it is that the clutches in the system should *not* need the friction additive, as under cornering circumstances, the mechanism should be unlocked anyway. Friction additives are to save the clutches and prevent chatter when posi/limited slip diffs need to actually differentiate. If the clutches aren't engaged in cornering, is there a need to use additive? Additionally, not using the modifier might actually provide "firmer" clutch apply to keep it from slipping at all.

    Mine's been running with the additive for over a year with no problems. I didn't know at the time that GM believes you shouldn't. You could always e-mail Eaton (www.eaton.com I think) and see what they say.
     
  3. tom

    tom 1/2 ton status

    Joined:
    May 20, 2000
    Posts:
    157
    Likes Received:
    0
    Location:
    So. Cal
    Been running my '86 suburban 14sf with gov lock for 160,000 miles using straight GL-5 lubricant and no addative. This is in accordance with my interpretation of the GM manual. I change it about every 15,000 miles. It has never had a problem and still works well in snow. THis vehicle doesn't get off road very often but I do rely on the gov-lok in the snow and it has always worked OK.
     
  4. chaka454

    chaka454 1/2 ton status

    Joined:
    Nov 13, 2001
    Posts:
    199
    Likes Received:
    0
    Location:
    California
    I threw in regular 80/90 oil and it works very well for me.
     
  5. RaisedK5

    RaisedK5 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    932
    Likes Received:
    0
    Location:
    Long Beach, CA
    You probably don't need to , at least i hope you don't cause i didn't on my sisters, BUT heres a quote from my factory manual

    Positive Locking or Positraction
    Every 6 months or 7,500 miles, whichever occurs first, check lubricant level and add lubricant, if necessary, to fill to level of filler plug hole.

    Drain and refill at first 15,000 miles then maintain same as standard axel but, use only the special positraction differential lubricant available at you authorized Chevrolet dealer.

    In addition to that little tid bit, i was told by the service manager at my local dealer that the Gov-loc needed an additive added to normal gear oil, so i dunno whats right, Tell Brian to throw a full floater with a detroit in it and solve the controversy once and for all/forums/images/icons/smile.gif
     
  6. morphed86k10

    morphed86k10 1/2 ton status

    Joined:
    Jun 25, 2001
    Posts:
    463
    Likes Received:
    0
    Location:
    Reno Nevada
    Detroit lockers: not just for traction anymore /forums/images/icons/smile.gif
     

Share This Page