1. Welcome to PlowSite. Notice a fresh look and new features? It’s now easier to share photos and videos, find popular topics fast, and enjoy expanded user profiles. If you have any questions, click HELP at the top or bottom of any page, or send an email to help@plowsite.com. We welcome your feedback.

    Dismiss Notice

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?

    Thanks
     
  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.....

    "GM CORPORATE 10-BOLT
    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:

    ~Chuck
     
  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!