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axle, diff numbers -- what do they mean?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 77Jimmy, Sep 15, 2002.

  1. 77Jimmy

    77Jimmy 1/2 ton status

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    Search done.

    I cleaned off my front axle (Dana 44) and found these numbers stamped on the axle...
    6037921 81267BE
    That 4th digit, the 7, could be a 1 though -- hard to tell.

    Also, on the back (facing the front of the vehicle) of my 12 bolt diff, I found these numbers w/ an N below them...
    6896839
    N
    The 1st digit, the 6, could be a 3.

    Do these numbers mean anything?
     
  2. beater74

    beater74 1/2 ton status

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  3. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    The numbers that matter are on the edge of the ring gear...ratio and build date.

    Rene
     
  4. 77Jimmy

    77Jimmy 1/2 ton status

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    Rene,
    Thanks, that's what I was looking for. I thought I saw somewhere that the numbers on the front axle meant something but guess not. I was just trying to confirm my gear ratios w/o actually having to pop open the diff (still need to get jack and jack stands). Actually, on the D44 there was a small metal clip under one of the bolts that say 43 14 -- done enough reading on this site to put the pieces together and determine that 43/14=3.07). Also, the RPO codes I have say 3.07 for the rear 12bolt as well. Looks like I'm 3.07 all the way around. /forums/images/icons/frown.gif /forums/images/icons/frown.gif
    This is kind of off topic but let me ask anyway...when my 31 inch tires crap out, would it be OK to move to a 33 inch tire w/o having to do any mods? 80+% of the time, I'm on pavement.

    beater74,
    Thanks for the website -- definitely a good source for diff info.
     
  5. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Well a 33" tire with the 3.07's isn't gonna hurt anything, but it sure isn't going to be a performer in town. My Jimmy was one step worse than that when I got it though. 33's and 2.73's /forums/images/icons/blush.gif but I had the 4 speed standard. I just used granny low as first gear and it was actually pretty good. 4th was like an overdrive on the freeway (1850 RPM @ 65 mph)

    The other issue to be aware of is sheet metal contact with 33's and no lift, depending on rim offset and width you may need to trim the back corners of your fenders. Mudhog ran 33's and no lift for a long time but his rims were 16" with a lot of backspacing which kept the tires away from the sheetmetal.

    Rene
     
  6. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

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    77Jimmy,

    you can go to 33's.....just make sure you don't have a RAPTOR 700R4 transmission!!!! /forums/images/icons/shocked.gif

    If this doesn't make any sense, don't worry. It's a carryover joke from a thread in "The Garage".... /forums/images/icons/smile.gif
     
  7. 77Jimmy

    77Jimmy 1/2 ton status

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    Not really worried about it being a street performer, just thinking it might look a little cooler. Am worried that if I go to a 33 inch tire, it would put a bunch more stress on the diff, t-case and tranny if I go off road. Not looking to do any serious rock climbing, more mudding and light trails.

    Glad you mentioned rims b/c I was about to do a search on them. Stupid question but how can I tell what size rims I have? Is there a code/number on them somewhere?
     
  8. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    If they are stock they'll either be 15x8 ralley rims or 15x7 plain steel. There was also a wagon style rim...not sure if it was 15x7 or 8 though.

    To avoid sheet metal problems just stuff the 33's on the factory rims. If you go with a standard 15x10 rim you'll have clearance issues for sure.

    I have a set of 35x12.5's on a set of factory 16.5x6.75 rims. close to 35,000 miles on them and no problems...

    Rene
     
  9. 77Jimmy

    77Jimmy 1/2 ton status

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    Thanks, Rene! /forums/images/icons/cool.gif
     
  10. R72K5

    R72K5 Banned

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    do you happen to know the RPO code for the 15" white rally wagon wheels or for the package they came with at least in 82 ?
    i have to prove this to someone locally who doesnt believe any such thing was factory.
    there also was a five lug 2wd version available too, but i am unsure what years, i believe older like '73-75 cuz cap screws come from behind and cap end is little and round and smooth around sides

    thanks
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    From your specs and usage, it sounds like you'd be a good candidate for the 33x10.5 BFG's in AT or MT.

    Both seem to fit stock trucks (which means stock wheels) without any clearance issues, but of course things like spring sag, vehicle weight, etc., is going to affect fit. Most tire shops will allow fitment/testing so that you don't end up with tires that rub.
     
  12. 77Jimmy

    77Jimmy 1/2 ton status

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    Thanks, Dorian.

    I'm a real tire dummy (among a long list of other things! /forums/images/icons/grin.gif ) -- is 15 the height, 8 the width? If so, the tape measure is my friend.
     
  13. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Sorry, 15 is the rim's diameter. 8" is the width of the rim.

    rene
     
  14. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Nope...I didn't believe it was a factory rim til recently when someone who had bought their K5 new showed a pic of the rims. I'd do a search but have no clue what key words would get me there.

    Blazer Boy maybe? It may have been his fathers truck??.. /forums/images/icons/confused.gif

    Rene
     
  15. dyeager535

    dyeager535 1 ton status Premium Member

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    If you are on a fast connection, play around here: http://www.slosh.com/cars/brochures/ I'm 99% sure that I saw mention of wagon wheels at least one year. I haven't seen ANY on '81 up trucks, and although that doesn't mean they didn't exist, they certainly were rare. Even the Aluminum wheels were fairly uncommon.

    BTW, there is a stamped in two letter code on your wheel ("JJ" comes to mind for some truck wheels) that can be looked up in a Hollanders manual (what the wrecking yards use to cross reference parts) that will tell you what the wheel is, diameter and width wise. Style wise too, but thats pretty obvious : )

    I believe that two letter code can be viewed if the trim rings are pulled off, probably near the valve stem.
     
  16. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Look at the 77 Jimmy Brochure...it's shown as an optional stylized steel wheel.

    Rene
     

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