1970 Build sheet rear axle codes

Discussion in 'The "Paper Trail"' started by Wildcat GS, Apr 15, 2016.

  1. Wildcat GS

    Wildcat GS Wildcat GS

    Is the rear axle code shown on the buildsheet for a 1970 GS 455 the same code which is stamped on the axle and listed in the service manual identification? Thanks in advance for any input,

    Tom Mooney
     
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    It isn't on my Production Order Body Final, just a box for Positraction rear. Duane decoded this for me years ago.

    [​IMG]
     
    Last edited: Apr 15, 2016
  3. Duane

    Duane Member

    Tom,
    If your car was built in Flint it would be on the POCP (Production Order Chassis Paint) sheet and not the POBF (Production Order Body Final) sheet.

    If it was built at a GMAD plant, the rear axle code would be on the Build sheet.

    Larry,
    I sent you a PM.
    Duane
     
  4. Wildcat GS

    Wildcat GS Wildcat GS

    Many thanks Larry and Duane. Car was built at Framingham so I assume that was a GMAD plant? The rear axle code on the build sheet is "OK" but I cant find reference to this code in my `70 shop manual?
     
  5. rtv72

    rtv72 Founders Club Member

    Tom,
    Did you check to see what code was stamped on the axle tube? The code on the build sheet could be a miss print. Does the car have A/C or non A/C? If you have non A/C the base differential is open 3.42. there would be axle code for posi G80 on the build sheet if it was ordered with one. I believe A/C cars came with 3.64 but not 100% sure of that, anything else is special order. I can look in my manual for you when I get home but it will not be until late Monday or Tuesday.


    open posi
    3.42------ OH-------OO
    3.64------ ---------ON
    3.91------ ---------OZ

    Ron
     
    Last edited: Apr 17, 2016
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I think the A/C Stage1 cars got the 3.42, non A/C cars got the 3.64. The A/C cars got the big A/C pulley (5 3/4"?) to slow the compressor down so it didn't reach belt-slinging speed:laugh:
     
  7. Duane

    Duane Member

    Tom,
    If memory serves me correct a Framingham "OK" rear is a Chevy 12-bolt open (not posi) rear with 2:56 gears.

    It is not a preferred gear ratio, but is a desirable housing and because it is under a Buick, it will have the larger u-joint pattern. (Like the Chevy Big Blocks had.)

    You can always get money for a 12 bolt Chevy housing if you decide to sell it.
    Duane
     
  8. Wildcat GS

    Wildcat GS Wildcat GS

    Hi Ron,
    I do have the service manual but thanks for the response and generous offer,
    Tom
     
  9. Wildcat GS

    Wildcat GS Wildcat GS

    Thanks Larry, non stage car. I think the standard GS 455 gearing was rather tall. Thanks for the response,
    Tom
     
  10. Wildcat GS

    Wildcat GS Wildcat GS

    Hi Duane,
    Is the 12 bolt rear axle described in the shop manual as the "C" type? The illustration appears to have 12 bolts securing the cover. If so, the codes listed in the shop manual for the open and posi 2:56 12 bolt are LJ and LY. The manual also states this rear axle was installed in Canadian built cars. Was the 12 bolt also installed in domestic assembly plants? Thanks again in advance for any response, I realize this type of fine info is hard earned,
    Tom
     
  11. Duane

    Duane Member

    Yeah, the "C" probably stands for Chevy.

    The 12 Bolt Chevy rears were available in Canadian built cars.

    ................However, the only 1970 Domestic Built Buick with a Chevy rear came from Framingham and was the Highway geared 2:56 open rear.

    There are people that continue to say some of the Flint cars came with them, but that was simply not the case. When these people with their supposedly "original" rear axles check the date codes for the rears, all their arguments go out the window.

    When I talked to the Buick Engineers about this they just laughed it off and basically asked why anyone would think they would put a Chevy rear under a Buick, when the Production Plant was run by Buick.


    As to why Framingham put "OK" on their GMAD build sheet...........who knows. The GMAD plants back then did some things differently. Some coded parts by colors, while others coded them by the last few digits of the part number.

    Your rear probably has the "L?" letters stamped on the tube.
    Duane

    PS. The "Factory" used many coding systems to reference things, and used them on different forms.

    At the top of your Build sheet, (as stated above) the codes used were often either colors, or the last few digits of the part number. Then at the bottom of your GMAD sheet it lists "UPC" codes.

    Then if you look at Larry's build sheet they are a totally different coding system and are called "Manufacturer Codes" These were used at the Flint plant only.

    Then Fisher Body had their own coding systems..............so the trick is to not mix & match the codes. A lot of this is due to jurisdictions.

    It often makes for a fun time trying to figure all this out.
     
  12. DioGS455Conv

    DioGS455Conv New Member

    Duane,

    I sent you a letter snail mail yesterday 7-7-2016, with some info I need decoded on this vehicle.

    I recently acquired an all original 1970 GS 455 Convertible, and the original large format GMAD sheet was found under the front seat, in excellent condition, all boxes and codes very legible.

    This can was delivered to buyer Nov 25, 1969, it was mfg at Leeds plant.

    In box 27 code is PC, in box 28 code is BA, in box 29, and in box 108, the Axle code OK

    Still can't find any info on what it means ?

    I won'y actually get the car until 7-15, at that point I can check the stamps on the axle itself.
     
  13. tsgp51

    tsgp51 Well-Known Member

    Good day Tom
    Hey I had a Framingham early gs 455 parts car with OK on the build sheet, it looked like the original rear and it was a 4 spider gear 3:23 posi gs 350's had that ratio but they had a 2 spider posi Carrier . special order maybe? I think Duane had a copy of the build sheet.
     
  14. tsgp51

    tsgp51 Well-Known Member

    We put that rear is in Duane 's gsx camino
     

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