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Is there a rear-axle differential breather?

Discussion in 'Early CJ5 and CJ6 Tech' started by ronnie victor, Sep 30, 2015.

  1. ronnie victor

    ronnie victor Member

    Folks -- I only recently realized there are such diff items, breather plugs, or vents. I learned the somewhat hard way (or, naive way) when doing my first diff drain and re-lube (66 cj5 restoration project), beginning with the front axle (dana 27). From top of the diff housing, I removed the springy cap and then the plug, thinking that was the fill port (okay, I since pumped in new gear oil into the cleaned and re-sealed diff cover port).

    Here's my question: I don't see (or feel) any such breather on the housing of the rear diff (dana 44)... nor does the FSM suggest any such vent. Is this true -- no venting of the rear differentials?? Or did I not look/feel around thoroughly enough on the top of the diff housing to locate one?

    When re-working the rear brakes, I cleaned out two pin-hole vents on the axle top near each of the brake plates ... only because the FSM shows those pin hole vents, and I figured I should locate and clean them. But is that it for venting the rear axle and differentials?

    -- thank you.... ronnie
     
  2. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Try a search here on "axle vent", it's come up a number of times in the past.

    H.
     
  3. uncamonkey

    uncamonkey Member

    You found the vents, such as they are on a CJ. Military Jeeps had a system that could pressureize the axles and gear boxes, as well as the motor for deep water crosings. Do a search, this has been discussed many times.
     
  4. Patrick

    Patrick Super Moderator Staff Member

    The vent is a small hole, in the left side axle tube, facing rearward.
     
  5. Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

     
  6. ronnie victor

    ronnie victor Member

    Thanks, Everyone, for replying and commenting. I have two pin-holes, one each side, near the grease fittings. So I gather from the comments that there is not a vent on the rear differential housing as on the front diff housing. That was my concern, that maybe I was missing something. But apparently all venting goes that 'long' distance from diff housing, thru the axle, to near the axle ends. Good enough.

    As an aside, last nite I successfully (first time) pumped in 6+ pints of GL-4 lube into my trans and transfer cases (~2.6 and 3.6 pts, respectively) -- after emptying out 49 y.o. oil (but the cj5 has been dormant 22+ years; ~70 k miles on it). It's a good feeling to get that lube replenishment done. Hopefully I can have this restoration project on the road by year's end. I'm the original owner; bought it in Athens, OH in '66
     
  7. Patrick

    Patrick Super Moderator Staff Member

    As I said, the vent is on the back of the driver's side axle tube, near the spring pad
    . It's common for them to become clogged up with dirt and seemingly disappear.
     
  8. uncamonkey

    uncamonkey Member

    I'm waiting for the famous picture that, I belive Walt has shown many times.
     
  9. Glenn

    Glenn Kinda grumpy old man Staff Member

    The zerks are on the back side of the axle though, the pinholes are on the very top as described. :)
     
  10. Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    (sigh)

    [​IMG]

    H.
     
  11. uncamonkey

    uncamonkey Member

    Sorrry, wrong name. I knew it was one of the oldtimers around here. A person could do as Patrick did and drill it out, tap it and add a vent hose to it and route to a higher place.
     
  12. Patrick

    Patrick Super Moderator Staff Member

    And I'm going to do this on my current CJ2A as well..;)
     
  13. nickmil

    nickmil In mothballs.

    There were some that had a vent hole on both tubes. The one in my '59/5 was like that. I found out after I hot tanked the axle housing and installed new gears and full float kit and it started leaking on both sides. I welded them up and moved the vent to a higher up location.
     
  14. oddfirejeeper

    oddfirejeeper Active Member

    could you do the grease zerk thing on a flanged axle so you can put grease in there? when i did mine i used that really tacky red grease and put a bit in there as the axle seal is at the end of the tubes