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.

Diff fluid change ?'s

Discussion in 'The Garage' started by chev4life, Feb 7, 2005.

  1. chev4life

    chev4life 1/2 ton status

    Joined:
    Jun 21, 2001
    Posts:
    416
    Likes Received:
    0
    Location:
    San Jose, CA
    Need to change fluid on my 14bolt w/detroit locker...what is a good weight and brand to go for? Also...should I use a paper gasket or a liquid gasket? Would black gasket goo work?
     
  2. Hossbaby50

    Hossbaby50 3/4 ton status

    Joined:
    Sep 1, 2001
    Posts:
    8,972
    Likes Received:
    0
    Location:
    Peoria, AZ
    How often do you run water or mud? If not often I would recommend what I use. I run Redline Heavy Shockproof gear oil. It is not cheap like dyno oil but it is a full synthetic and is very good stuff. It is roughly a 75W-250. I use RTV for gaskets on differentials. Seems to work fine for me.

    Harley
     
  3. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

    Joined:
    Aug 28, 2002
    Posts:
    9,097
    Likes Received:
    144
    Location:
    california
    I would only use synthetic gear oil if you keep it out of the mud and water. It only costs a couple extra dollars for synthetic over dyno oil. It will keep the gears cooler and break down slower than dyno oil, and in an area like a rearend that is almost always neglegted, an oil that can resist breakdown and wear the longest should be used IMHO.

    I use both the paper gaskets and high tack RTV.
     
  4. dontoe

    dontoe 3/4 ton status GMOTM Winner

    Joined:
    May 7, 2004
    Posts:
    9,070
    Likes Received:
    0
    Location:
    Hickory, N.C.
    Wal-mart brand O.K.?
     
  5. chev4life

    chev4life 1/2 ton status

    Joined:
    Jun 21, 2001
    Posts:
    416
    Likes Received:
    0
    Location:
    San Jose, CA
    I like the mud and the water, but would like to put synthetic in. I talked to a detroit locker guy at SEMA this year and recommended not running synthetic on the lockers...has anyone ever heard this? What weight do I run if its not synthetic?
     
  6. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

    Joined:
    Aug 28, 2002
    Posts:
    9,097
    Likes Received:
    144
    Location:
    california
    For dyno oil I would use 85w140, or 80-90. For synthetic I used Mobile 1 syn. 75w-90 in my D70. I would have prefered a little heavier oil but got it for free so I can't complain.
     
  7. Hossbaby50

    Hossbaby50 3/4 ton status

    Joined:
    Sep 1, 2001
    Posts:
    8,972
    Likes Received:
    0
    Location:
    Peoria, AZ
    My rear axle is welded so that isn't an issue with my synthetic fluid. My lockright has been in synthetic fluid for the 3 years I have had it and for awhile when the previous owner ran it.

    Lots of people complain that there lockright is loud, but I have never heard a sound from my lockright with my thick synthetic fluid that I run.

    Harley
     
  8. K5MONSTERCHEV

    K5MONSTERCHEV 1/2 ton status

    Joined:
    Jan 27, 2003
    Posts:
    3,254
    Likes Received:
    0
    Location:
    Castro Valley, CA
    Red line is good. If not 80-90W is fine. And silicone, no gasket.
     
  9. cbbr

    cbbr 1 ton status GMOTM Winner

    Joined:
    Jul 17, 2004
    Posts:
    14,681
    Likes Received:
    0
    Location:
    High velocity, Low altitude
    I am running open diffs, but I used Mobile 1 synthetic - 75w-90 - per the recommendation of many members. I also used an original GM gasket with a very thin coat of RTV in the rear and just RTV in the front. Takes about two gallons to do both axles.
     
    Last edited: Feb 8, 2005
  10. ssls6

    ssls6 Registered Member

    Joined:
    Jan 5, 2005
    Posts:
    86
    Likes Received:
    0
    Location:
    Dallas, TX
    I like Schaeffers #267. It contains moly and climbs really well.
     
  11. bigyellowjimmy

    bigyellowjimmy 1/2 ton status

    Joined:
    Jan 15, 2004
    Posts:
    2,105
    Likes Received:
    0
    Location:
    Chandler, AZ
    I use Valvoline 80W/90 but I dont travel at high speeds or loaded, if it was a highway/tow rig I'd use synthetic :thumb:
     
  12. pauly383

    pauly383 Daddy383 Staff Member Moderator

    Joined:
    Jul 22, 2001
    Posts:
    16,217
    Likes Received:
    1
    Location:
    Mesa , Arizona USA
    I also run Redline , on Harley's reccomendation , for 4 months now with no problems . It likes to stick to everything , which is good . I swapped axles from my 3.08's to my 3.73's , whole housings , and when I went to roll the project truck which has teh old axles now , the damn thing still has a pretty good coating of Redline on it , and no surface rust from the morning dew :D
     
  13. chev4life

    chev4life 1/2 ton status

    Joined:
    Jun 21, 2001
    Posts:
    416
    Likes Received:
    0
    Location:
    San Jose, CA
    So I will see if I my parts store has a gasket if not I will just use RTV. How high much do you usually put in when refilling? I have a 14FF and dana 44 that I will be doing. I will also see what my parts store has in terms of fluid, I am a big fan of modil 1 from my SS so maybe I will go that route.
     
  14. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

    Joined:
    Aug 28, 2002
    Posts:
    9,097
    Likes Received:
    144
    Location:
    california
    I don't really remember how much the 14's hold but I just changed the oil in my D70 and it seemed to hold about 6 quarts, hard to tell because I was using a hand pump and a 5 gallon bucket. THere is a plug in the side of the diff, on the pass. side IIRC. Get it out with your 3/8" ratchet and fill through that hole until oil starts to spill out the bottom of your plug hole.
     
  15. rjfguitar

    rjfguitar 3/4 ton status GMOTM Winner

    Joined:
    Aug 28, 2002
    Posts:
    9,097
    Likes Received:
    144
    Location:
    california
    You know it! In the D70 under my DOdge cummins I run syn. because it sees high speeds and tows a lot. Obviously that would cause the most heat and wear, and that is where the synthetic should shine. In my K5 that just sees short high speed bursts and slow wheeling I use any 80-90 dyno oil :thumb:
     
  16. chev4life

    chev4life 1/2 ton status

    Joined:
    Jun 21, 2001
    Posts:
    416
    Likes Received:
    0
    Location:
    San Jose, CA
    Yeah, I get alot of highway miles...even when I do wheel...got to get there. I am thinking of useing the 75x90ns Redline, my parts place has it in stock...I figure I will just clean their stock out :D. Yeah I figured that is what I do with the fill hole...thanks for info!
     
  17. 79Beast

    79Beast 1/2 ton status

    Joined:
    Dec 9, 2001
    Posts:
    1,155
    Likes Received:
    0
    Location:
    Georgia
    For my trail truck with D60/FF14 combo with Detroits in both, I use Coastal 80W90 that I buy in a 5 gallon bucket. I change it out every six months or so in the front and yearly in the rear. More often of course if I run deep water or mud. Also, I prefer RTV to paper gaskets for differential covers. In my street driven truck, I used Mobil 1 75w90 with good results.
     

Share This Page