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Late 90s S10 with 8.5" 10 bolt... what splines?

Discussion in 'The Garage' started by sled_dog, Jan 31, 2006.

  1. sled_dog

    sled_dog 1 ton status

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    My buddy has a late 90s S10 Blazer. The thing is a bit of an oddity. It has every option(except the ZR2 package) but is 5 speed. It even has an 8.5" 10 bolt under the back. So does anyone have a clue what spline count the axleshafts are? He wants to get a spool since he killed the factory locker and found out they are considered junk by the ZR2 guys. I figured 30 spline, he says Summit has, 28, 30, and 33 spline. Anyone?
     
  2. goldwing2000

    goldwing2000 Guest

    I think it would be a 30. I would pull an axle to be sure. That way you don't waste money buying the wrong parts.
     
  3. Slapperbar

    Slapperbar Retired Navy NDT Examiner Premium Member

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    Buy axels with the spool and upgrade to 33 spline.
     
  4. sled_dog

    sled_dog 1 ton status

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    I have a feeling if he starts spending money on stuff like that, its going to get a 9" or something else going under it. Hes aiming for cheap stuff at the moment.
     
  5. Slapperbar

    Slapperbar Retired Navy NDT Examiner Premium Member

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    The superiors in mine wern't bad. I also putoneof the SLP takeout Zexel diffs in it.
     
  6. dave_90_blazer

    dave_90_blazer 1/2 ton status

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    should be 30 , but I agree, pull and axle to make sure
     
  7. 79chevyk10

    79chevyk10 1/2 ton status

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    If only seen 8.5" 10 bolts in S-10's with the vortec (vin W) high output V6 with a manual trans or the ZR2's. Most all the other 4x4's and 2wd's I see at work all have the 7.5" 10 bolt with 28 spline. Either way I do believe that they have 28 spline axles.
     
  8. Slapperbar

    Slapperbar Retired Navy NDT Examiner Premium Member

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    Don't go by that. They "stopped" putting the 26 spline 7.5 in in '90. I still got one in my '91.
     
  9. 79chevyk10

    79chevyk10 1/2 ton status

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    Who said anything about 26 spline. Those are on the old S-10s.
     
  10. 79chevyk10

    79chevyk10 1/2 ton status

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    Not true. They went from 26 spline to 28 spline in 89' I believe. My 99' has a 7.5" 10 bolt with 28 splines.
     
  11. sled_dog

    sled_dog 1 ton status

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    I think the point was, there are almost always exceptions and it is hard to say when things change when they changed a lot.
     
  12. Slapperbar

    Slapperbar Retired Navy NDT Examiner Premium Member

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    You are right on the 89' thing. My '91 still came with 26 splines.
     
  13. u2slow

    u2slow 1/2 ton status

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    28-spline started in 88.5 when they put the 4.3L in the S10. The 4-bangers and 2.8L trucks still got 26-spline until the the body style changed.

    The 8.5" 10b axle in the ZR2 and 4.3L/5-spd trucks is 30-spline. 2wd, 4wd, and ZR2 are all different widths - so watch out.

    The 33-spline is aftermarket.... it started as a 'cheat' to get a bigger shaft into a stock Ford 9" third. Now there's 33-spline stuff for the 10b, 12b, D44, etc.
     
  14. beater_k20

    beater_k20 Banned

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    did you buy it new?
     
  15. mikey_d05

    mikey_d05 1 ton status GMOTM Winner

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    Ok, I'm gonna break it down since nobody else has the cajones, spline count in S10's is a cluster****. My friend has a non-ZR2 '00 with an 8.5" 10 bolt. Pull a shaft and save frustration.
     

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