1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

How to verify if its a long or short pinion 10.25

Discussion in '6.9L IH & 7.3L IDI Diesels' started by jimcaf12, Jan 15, 2020.

  1. jimcaf12

    jimcaf12 Registered User

    Posts:
    21
    Likes Received:
    2
    Joined:
    Jan 1, 2016
    Location:
    N county San Diego
    My 1987 door tag shows I have a C5 axle supposed to be 410 Limited slip anyway I opened it up and its a 355 open diff,so im not sure if it was miss tagged or if the rear end was swaped,so Im doing a gear change and a Yukon posi ,I have it torn down wanting to order parts hoping there is a way to measure the pinion to verify weather its a short or long,,,thanks ahead for responses
     
  2. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

    Posts:
    8,133
    Likes Received:
    6,583
    Joined:
    Jul 27, 2015
    Location:
    Bulverde, Texas
    Does it have a vss sensor on the pumpkin?
     
  3. austin92

    austin92 Full Access Member

    Posts:
    970
    Likes Received:
    280
    Joined:
    Jul 20, 2016
    Location:
    Brazil. IN
    All modern production gears are 10.5 and long spline because it’s interchangeable. I have the yoke off a short spline pinion on my long spline 3.73 gears. Axle was a 10.25 out of a 94, new gears are 10.5 on a Detroit truetrac.


    Sent from my iPhone using Tapatalk
     
  4. jimcaf12

    jimcaf12 Registered User

    Posts:
    21
    Likes Received:
    2
    Joined:
    Jan 1, 2016
    Location:
    N county San Diego
    Thewespaul Yes it does have the VSS sensor on it
     
  5. jimcaf12

    jimcaf12 Registered User

    Posts:
    21
    Likes Received:
    2
    Joined:
    Jan 1, 2016
    Location:
    N county San Diego
     
  6. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

    Posts:
    809
    Likes Received:
    356
    Joined:
    Jun 9, 2008
    Location:
    Central Cal Foothills
    The VSS is not a for sure way to know, my 91 had a short pinion and vss. I’m really testing it out now, I swapped axles with my 96 so now the short pinion is behind the 460 hp 1000 ft lb Powerstroke!
     
  7. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

    Posts:
    8,133
    Likes Received:
    6,583
    Joined:
    Jul 27, 2015
    Location:
    Bulverde, Texas
    Now that’s an odd one, what was the speedo driven off of? Is it a 91 model or 91 build year?
     
  8. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

    Posts:
    809
    Likes Received:
    356
    Joined:
    Jun 9, 2008
    Location:
    Central Cal Foothills
    The speedo is cable driven but the ABS uses the VSS. 87-91
     
    IDIoit likes this.
  9. Thewespaul

    Thewespaul Supporting Vendor Supporting Member

    Posts:
    8,133
    Likes Received:
    6,583
    Joined:
    Jul 27, 2015
    Location:
    Bulverde, Texas
    Man that’s weird, I’ve got a 91 parts truck with vss and long pinion I’m putting eyes on here, learn something new every day.
     
    DaveBen likes this.
  10. snicklas

    snicklas 6.0 and Loving It!! Staff Member

    Age:
    45
    Posts:
    5,487
    Likes Received:
    1,420
    Joined:
    Aug 7, 2006
    Location:
    Greenfield, Indiana
    Any IDI Era truck with RABS will have a VSS in the rear Differential, that's what rums the RABS.

    87-91 the diff VSS is only for the RABS, it's a cable driven speedometer, and if it has an E4OD, there is another VSS "Dongle" that plugs into the speedo cable at the transmission/transfer case that's only for the TECA.

    92 up (and for certain through the 6.0 trucks, probably even the brand new ones) the VSS in the diff runs the ABS and the speedo.
     
    Jason1377 likes this.
  11. austin92

    austin92 Full Access Member

    Posts:
    970
    Likes Received:
    280
    Joined:
    Jul 20, 2016
    Location:
    Brazil. IN
    The pinion gears are the same length. Splines are just longer for more strength.


    Sent from my iPhone using Tapatalk
     
  12. jimcaf12

    jimcaf12 Registered User

    Posts:
    21
    Likes Received:
    2
    Joined:
    Jan 1, 2016
    Location:
    N county San Diego
    Thanks Austin,,
     
  13. ifrythings

    ifrythings Full Access Member

    Posts:
    620
    Likes Received:
    366
    Joined:
    Dec 17, 2011
    Location:
    BC
    If I remember right, I think the long pinion used straps to hold the u-joint as where the short pinion used u-bolts to secure the u-joint.
     
  14. Garbage_Mechan

    Garbage_Mechan Garbage Mechanic

    Posts:
    809
    Likes Received:
    356
    Joined:
    Jun 9, 2008
    Location:
    Central Cal Foothills
    I wish it were true but I just looked at my 91 short pinion spline and 96 long pinion spline and both have straps. Visually the short is 3/4 inch from the shortest point to the seal guard and the long is 1 1/2 so comparing the two you can see the length.
     
    Thewespaul likes this.
  15. Philip1

    Philip1 Full Access Member

    Posts:
    79
    Likes Received:
    55
    Joined:
    Apr 1, 2019
    Location:
    Nevada
    Looking online it looks like there is a measurable difference in the yoke length[​IMG]

    Sent from my SM-G975U using Tapatalk
     

Share This Page