Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

a little gear ratio help please?

Discussion in 'The Garage' started by 1badv10, Jun 9, 2004.

  1. 1badv10

    1badv10 Registered Member

    Joined:
    Feb 26, 2004
    Posts:
    74
    Likes Received:
    0
    Location:
    new york
    hey guys i have an '87 1/2 ton p/u. yesterday it got hungry and ate the rear end.. I have always assumed it has 3.08 gears how do i tell quickly? i was able to get these #s off the large (41 tooth) ring gear -2 GM 1235128 ?2 41 3 87- the ? i am unsure what that is could be a # or a . thanks for any help
     
  2. readymix

    readymix 3/4 ton status

    Joined:
    May 30, 2004
    Posts:
    6,706
    Likes Received:
    26
    Location:
    Murrieta, California
    looks like 3.42 to me
     
  3. 1badv10

    1badv10 Registered Member

    Joined:
    Feb 26, 2004
    Posts:
    74
    Likes Received:
    0
    Location:
    new york
    [ QUOTE ]
    looks like 3.42 to me

    [/ QUOTE ] how do you tell that? cause i need to be sure so i can order the new parts..thanks again.. also i can still read the tag in the glovebox anyone know how to decode for a ratio?
     
  4. Greg72

    Greg72 "Might As Well..." Staff Member Super Moderator

    Joined:
    Mar 5, 2001
    Posts:
    15,684
    Likes Received:
    1,392
    Location:
    642 Days to BB2018
    Hey,

    The last two numbers in that sequence "3 87 " are the month and date stamp. Ring gear was built in March 1987.

    The two numbers before that are the ring and pinion ratio "?2 41". In this case there are 42 teeth on the ring gear and that "?2" has probably got to be a "12" for the pinion...it's the only thing that makes sense numerically.

    Divide 41 by 12 and you get a 3.42 ratio.....


    If you have the RPO code for the rear axle, you should be able to post that here and someone can confirm that it matches what was just calculated.

    Good luck.


    /forums/images/graemlins/thumb.gif
     

Share This Page