GM Truck Club
THE PREMIER CHEVY TRUCK & SUV FORUM
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER
Results 1 to 8 of 8
  1. #1
    Jr. Apprentice
    Join Date
    May 2010
    Location
    Ft Collins, CO
    Posts
    21

    Default Easy to tell gear ratio?

    Is there an easy way to tell what my gear ratio is? I bought a 91 K2500 last week and it needed the oil coolant lines replaced. I went down and got some only to find that they weren't the right ones. The guy at NAPA swapped me for the lines to the "higher" gear ratio trucks and these ones work great...he said it was 410 or 456 ratio. I just want to make sure I get it right so I dont need to go through this crap again in the future.

    For Reference its the 91 K-2500 light duty(?) 6 lug rear end with the 350;5.7L Auto 4x4.
    1991 Chevy K2500 4x4 Light duty (350 and 6 lug ><) still basic.

    Previously
    1988 Chevy 1500 Suburban 3" lift 35" tires basic

  2. #2

    Default

    You can check your RPO sticker in the glove box, or pull your rear diff cover. It's marked on the ring gear.

    I can't imagine an LD 2500 having 4.56. Or 4.10, truthfully.
    Last edited by 2COR517; 05-07-2010 at 07:49 PM.
    When you hear hoofbeats, look for horses not zebras.

  3. #3
    Jr. Apprentice
    Join Date
    May 2010
    Location
    Ft Collins, CO
    Posts
    21

    Default

    Im not really sure myself...the title says 2500 and it has the Overdrive Automatic...the NAPA man said the high gear ratio trucks were few and far between, that's why he gave me the regular lines to begin with. Thanks for the reply too I'll check and put it down somewhere so I remember next time ><
    1991 Chevy K2500 4x4 Light duty (350 and 6 lug ><) still basic.

    Previously
    1988 Chevy 1500 Suburban 3" lift 35" tires basic

  4. #4

    Default

    List your RPO codes if you can and I can try and find out.
    Bagged 06 Silverado Crew Cab.

  5. #5
    Master Mechanic bigdaddy77084's Avatar
    Join Date
    Jan 2010
    Location
    Houston, Texas, United States
    Posts
    649

    Default

    Here are the codes for gear ratios
    GU4....3.08
    GU5....3.23
    GU6....3.42
    GT4....3.73
    GT5....4.10
    __________________
    95 tahoe 2dr 4x4 200,000+ miles

  6. #6
    Jr. Apprentice
    Join Date
    May 2010
    Location
    Ft Collins, CO
    Posts
    21

    Default

    Didn't really know what to look for on that RPO sticker but there is a GT5...So thank you bigdaddy :D that'll help out. You guys know where to find how to read that RPO? Or is it a service thing.
    1991 Chevy K2500 4x4 Light duty (350 and 6 lug ><) still basic.

    Previously
    1988 Chevy 1500 Suburban 3" lift 35" tires basic

  7. #7

    Default

    I look through this website http://www.rpocodes.com/
    Bagged 06 Silverado Crew Cab.

  8. #8
    Jr. Apprentice
    Join Date
    May 2010
    Location
    Ft Collins, CO
    Posts
    21

    Default

    Thanks ZSI52...that'll be sweet in the future, man you guys are awesome :D
    1991 Chevy K2500 4x4 Light duty (350 and 6 lug ><) still basic.

    Previously
    1988 Chevy 1500 Suburban 3" lift 35" tires basic

Similar Threads

  1. Need help with choosing a gear ratio.
    By fx2offroad in forum Lifted & Offroad Suspension
    Replies: 2
    Last Post: 01-10-2010, 07:09 PM
  2. what gear ratio?
    By dustin_742 in forum General Chevy & GM Tech Questions
    Replies: 16
    Last Post: 12-09-2009, 06:24 AM
  3. What gear ratio should I have?
    By drumrob in forum Lifted & Offroad Suspension
    Replies: 4
    Last Post: 03-17-2009, 07:00 PM
  4. Gear ratio
    By stringbender in forum General Chevy & GM Tech Questions
    Replies: 4
    Last Post: 02-08-2009, 05:49 PM
  5. What gear ratio are you running?
    By MrShorty in forum GM Powertrain
    Replies: 6
    Last Post: 02-08-2008, 08:54 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •