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12b rear diff cover off for 1st time...what should I be looking for?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 77Jimmy, Jun 17, 2003.

  1. 77Jimmy

    77Jimmy 1/2 ton status

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    Hey guys...rookie (me) needs some guidance here...would appreciate your input.

    Pic just after taking off the diff cover for the 1st time. Have some Brake Clean but am hesitant to blast away with it until I know what I'm doing. Teeth look pretty good in my rookie opinion, some small chips on the spider gears. I spun the left wheel forward and the right wheel did not spin. When I spun the left wheel backward/reverse the right wheel did spin. Also, there was just a very small amount of play when I switched directions on the left wheel...I could see the pin in the middle move ever so slightly. Hope that makes sense.

    What should I be looking for...good, bad, ugly, etc?

    Also, what the heck do I have here? Is this the infamous gov-loc?

    Also, I've read about a stamp somewhere that will tell the gear ratio but I couldn't find it. My RPO code says 3.08 but I'd like to know for sure. What teeth can I count to get that?

    Sorry for all the questions but I'm just getting started so any help would be appreciated! /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

    [​IMG]
     
  2. tmaxxer9

    tmaxxer9 1/2 ton status

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    some gears and oil leaking out of pumpkin.
     
  3. Rolled

    Rolled 1/2 ton status

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    I used 1.25 cans (big cans) of carb cleaner on my 12 bolt the other day. It cleaned it up real nice.

    It is a standard open rear diff.

    To tell the gear ratio - There will be a series of numbers stamped on the ring gear. There will be a date and a set of numbers that corespond to the number of teeth.

    Example

    11 41 = 3.73 (41/11 = 3.727272727272)
    12 41 = 3.42
    14 43 = 3.08

    If there is no numbers stamped on the ring gear then just count the number of teeth on the ring and the pinion and divide them.

    Example of a 3.73

    41 teeth on the ring gear
    11 teeth on the pinion

    Good luck
     
  4. 77Jimmy

    77Jimmy 1/2 ton status

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    Thanks, Rolled. /forums/images/graemlins/thumb.gif

    I'm pretty sure this is the original axle so it has about 125k miles on it. What are the signs that this thing is about to blow or has another 50k miles in it? /forums/images/graemlins/grin.gif

    Also, I've read other posts saying that the spider gears were loose...how loose is loose and how do I check that?

    Also, since I don't have the gov-loc I don't need that special oil right? Just straight up gear oil? Final question, what's the correct amount to add?

    Thanks! /forums/images/graemlins/thumb.gif
     
  5. BlazerGuy

    BlazerGuy 3/4 ton status

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    Yeah, you don't need the special lube(even if you did have the govlock, you probably wouldn't need it since it wouldn't work anyway!) just gear oil. IIRC it takes about 2.5 quarts...
     
  6. 77Jimmy

    77Jimmy 1/2 ton status

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    Thanks BlazerGuy! /forums/images/graemlins/grin.gif /forums/images/graemlins/thumb.gif
     
  7. Rolled

    Rolled 1/2 ton status

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    I asked the same question about the Fluid Capacity too. I poured in 2.5 and opened the plug and let the rest out. I think it held about 2.25 quarts.
     
  8. 77Jimmy

    77Jimmy 1/2 ton status

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    Thanks again, Rolled! /forums/images/graemlins/thumb.gif
     
  9. 77Jimmy

    77Jimmy 1/2 ton status

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    Finally got my new chrome diff cover (arrived a day later than they said it would) and put that on last night...wouldn't you know that the bolts that came w/ the diff cover were too long???!!! /forums/images/graemlins/angryfire.gif So I had to use the old bolts to make it work. 4wpw will be getting a call from me.

    Anyway, I confirmed via the #s on the ring that I do in fact have 3.08 /forums/images/graemlins/frown.gif

    Also, my diff held a hair less than 2 quarts. This is a little bit less than some of the other amounts I have seen. I think I'm fine but is it better to have to much or too little in your rear diff?
     

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