Author Topic: 1986 GMC axle regear questions  (Read 965 times)

Offline Snag

  • Newbie
  • Posts: 6
  • Newbie
1986 GMC axle regear questions
« on: May 09, 2023, 08:35:12 PM »
  I'll be doing a swap from 2.73's to 3.42's on my truck and have a couple of questions . First off , I need to find pinion depth , I have a couple of ideas on how to measure from ring carrier center line ... These ideas involve machining (I have a quite complete home machine shop) a shaft with a flat spot and discs at both ends to center it in the bearing cups . Is there a tool I can copy or am I on my own for design ? Another question is how to lock down the pinion shaft when checking gear lash ? I'll be using a spacer sleeve and shims instead of the crush sleeve so that part is fairly easy . I have most of the tooling needed , what I don't have I can make in the shop ... but for some of these things I need a sample to copy . Right now I'm wishing it was as simple as when Dad re-geared the '59 Merc ... Unbolt one chunk and bolt in the other , slap the axles back in and roll .

Offline zieg85

  • Global Moderator
  • Senior Member
  • ****
  • Posts: 7516
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
Re: 1986 GMC axle regear questions
« Reply #1 on: May 10, 2023, 12:13:16 PM »
I watched several videos on YouTube and decided even though mechanically I could do it and it would be a good excuse to buy some specialty tools needed, I would pay someone who has done it before
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 18915
Re: 1986 GMC axle regear questions
« Reply #2 on: May 10, 2023, 05:09:24 PM »
There are multiple ways you can find the centerline and measure depth. If you have the ability to make your own tooling it should be pretty simple. 10 bolt?
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10