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Identification of rearend?

Discussion in 'Chevy Trucks' started by Hoggin GMC, Mar 28, 2002.

  1. Hoggin GMC

    Hoggin GMC Junior Member
    Messages: 13

    Hi, I own a 85' GMC Sierra 1500 4x4 1/2 ton. I want to know what kind of rear i have in it so I can put better axles and gears in it. It has 10 Bolts on the differential case. Would this be a 10 bolt? Or a Dana of some sort?

  2. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    You have the 10 bolt,e 8.5" semi floating rea axle
  3. Hoggin GMC

    Hoggin GMC Junior Member
    Messages: 13

  4. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    Your welcome.
  5. K20

    K20 Junior Member
    Messages: 2

  6. Chuck Smith

    Chuck Smith 2000 Club Member
    from NJ
    Messages: 2,317

    From the link you posted.....

    This 10-bolt, with a larger 8 1/2-inch ring gear diameter, replaced the Dana 44 that was used in the front of some pre-1977 GMs. It can also be found in the back of 1983-91 1/2-tons and in the front of 1983-87 1/2-tons."

    Which is exactly what John D said.....Most Chevy truck nuts know that GM stopped using the 12 bolt in 1/2 ton models in 83 (though some 82's had 10 bolts in the rear). Especially anyone that has overloaded and worked a truck with a 10 bolt rear hard. Most want to upgrade to a 12 bolt, and "Tim The Tool Man Taylor" types upgrade to the full floater 14 bolt..... The 10 bolt is more of a car axle IMO.

    I had a buddy that replaced (3) 10 bolts in his 95 in 140,000 miles. On the other hand, my 80 GMC has 140,000 miles on the original full-floater GM 14 bolt rear axle.

    In any case, Hoggin would be better off getting a 12 bolt and rebuilding it if necessary, rather than upgrading the weak 10 bolt. Even "upgraded" the 10 bolt is a weak axle.
    The 12 bolt is just shy of the 9" ring gear diameter of the small GM semi-floater 14 bolt.

    Stepping off the soapbox now..... :drinkup:

  7. guilty1

    guilty1 Junior Member
    Messages: 29

    I just broke the 12 bolt in my '78 k10:mad: along with the slip joint on the driveshaft:realmad: ......seems like having it rebuilt by a pro is going to cost more than I paid for the vehicle!

    I was thinking of running a steeper gear, anyway, (need more gear to turn them 33s") , so I am wondering about that 14 bolt....are any of the 14 bolt rearends, 1/2 ton rears?....I imagine the axles are thicker in a 3/4 ton, along with needing 16" wheels for drum clearance (there go my 33"s). And if i find a set of 3/4 ton rearends....could I still use my 1/2 ton suspension? will the rest of the drivetrain bolt up?i.e. transfer case, driveshafts, 4-speed....also does anyone know a good site for direction on how to swap the rear? ANY help would be appreciated!