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.

axles, axles!!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by santana, Feb 20, 2003.

  1. santana

    santana 1/2 ton status

    Joined:
    Jan 11, 2003
    Posts:
    1,483
    Likes Received:
    0
    Location:
    Mesa Arizona
    How can you tell what type of gears are on a specific axle? Also, what is the difference in gear ratios from say 3.73 & 4.11?
     
  2. sled_dog

    sled_dog 1 ton status

    Joined:
    Sep 3, 2002
    Posts:
    16,870
    Likes Received:
    0
    Location:
    Austin, TX
    if you mean what the gear ratio is, a real general way of doing it is turn the pinion by hand and mark the tire or drum, watch it and see how many turns of the pinion it takes for the tire or drum to make one complete revolution. If it takes say 4.5 turns well thats most likely a 4.56. Like I said real general. As for the difference in gear ratios I won't even begin to explain this its just I don't know I'm not sorry.
     
  3. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

    Joined:
    Jan 21, 2001
    Posts:
    20,716
    Likes Received:
    2
    Location:
    Undisclosed Location
    Here's the lowdown on gears.....

    When you have a higher number, such as 4.11 or 4.56, that is refered to as a lower gear and when the number is lower such as a 3.42 or 3.73, it's refered to as a higher gear ratio. Don't ask, just the way it is.

    As for the meat of the subject, when you have a higher gear ratio (lower numerically) you will have a higher top speed, but your torque will suffer and will not get up to speed as good.

    The opposite is true for the lower (higher numberically) gear ratios. You will get off the line faster, but your top speed suffers. Not really applicable for us is the top speed facet, but with the lower gear ratio, the engine and transmission works less and in low speed situations such as rockcrawling, this is what you want.

    Tires affect the overall ratio also. A taller tire will give you a higher gear; whereas a shorter tire will give you a smaller gear ratio.

    Example. I currently run a 3.73 gear in my rearend with 35" tires. The 3.73 number is in effect a 3.4something gear and it's now a higher gear. My torque has suffered with this change. If I want the 3.73 back, I would have to change to a 4.11.

    Did that confuse you enough? /forums/images/graemlins/thumb.gif
     
  4. santana

    santana 1/2 ton status

    Joined:
    Jan 11, 2003
    Posts:
    1,483
    Likes Received:
    0
    Location:
    Mesa Arizona
    Well, Ive got 32's and use it as a daily driver so I was trying to figure out what type of ratio should be best to use also how to check what type of gears are on axles.
     
  5. santana

    santana 1/2 ton status

    Joined:
    Jan 11, 2003
    Posts:
    1,483
    Likes Received:
    0
    Location:
    Mesa Arizona
    I took the pinion turn test like you posted and looks like it turns 3 and 3/4 turns so that would make it a 3.73 right? or close..
     
  6. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

    Joined:
    Jan 21, 2001
    Posts:
    20,716
    Likes Received:
    2
    Location:
    Undisclosed Location
    3.73 is a real good ratio to run, but a little higher gear will be fine.

    The best surefire method for finding out what ratio you have is to pop open the diff cover(I'm sure the fluid needs to be changed anyway). Count the number of teeth on the ring gear, which will be the large one on the left side that is straight up and down. Then count the number of teeth on the pinion gear, with is the mushroom looking gear that is inside the pumpkin, all the way to the inside. Then divide the ring gear number by the number on the pinion gear will give you your gear ratio.

    I think that some gears will have the ratio stamped on them, not for sure.
     
  7. K5thatShmobs

    K5thatShmobs 1/2 ton status

    Joined:
    Sep 27, 2001
    Posts:
    353
    Likes Received:
    0
    Location:
    San Luis Obispo, CA
    Also, the ratios themselves refer to how many times the pinion is spinning in order to spin the tires one full rotation. (Ex. A 4.56 ratio means that the pinion has to spin 4.56 times in order to make the tires turn one rotation.) Interestingly enough, GM also correlates the actual number of teeth on the pinion and ring gear with the ratio. (Ex. A gear set with a 4.10 ratio will have 41 teeth on the ring and 10 teeth on the pinion; 41/10=4.10 thus, the ratio is 4.10:1)

    Glad to add to the confusion.
     
  8. santana

    santana 1/2 ton status

    Joined:
    Jan 11, 2003
    Posts:
    1,483
    Likes Received:
    0
    Location:
    Mesa Arizona
    When you say higher gear, do you mean like a 3.42?

    Thanks for explaining /forums/images/graemlins/thumb.gif
     
  9. santana

    santana 1/2 ton status

    Joined:
    Jan 11, 2003
    Posts:
    1,483
    Likes Received:
    0
    Location:
    Mesa Arizona
    The reason I ask is b-cause I bought a K5 cheap but with no rear end and picked one up for $50 its off a later model 3/4 ton chevy 10 bolt which is actually as wide as the front axle which will even out the axles Id just have to relocate the perches and buy some metric lug nuts for it and possibly re-do the brake lines, as far as





    i can see.
     
  10. sdavid

    sdavid 1/2 ton status

    Joined:
    Aug 5, 2002
    Posts:
    244
    Likes Received:
    0
    Location:
    Livingston, TX
    Check in your glove box for the RPO codes. Look for something that has a G at the beginning, like GT5 or GU6. That will be your ratio. Do a search for RPO Codes and that will give you the translation. A '89 has a good possibility of being 3.73. Good ratio, especially for 33" tires and down. /forums/images/graemlins/thumb.gif
     
  11. sled_dog

    sled_dog 1 ton status

    Joined:
    Sep 3, 2002
    Posts:
    16,870
    Likes Received:
    0
    Location:
    Austin, TX
    won't work he got a rear from another truck
     
  12. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

    Joined:
    Jan 21, 2001
    Posts:
    20,716
    Likes Received:
    2
    Location:
    Undisclosed Location
    A higher gear will be a lower number gear and the opposite for a lower gear. 2.73 is a high gear, 4.56 is a low gear.
     
  13. Poohbair

    Poohbair 1/2 ton status

    Joined:
    Jan 30, 2003
    Posts:
    2,139
    Likes Received:
    0
    Location:
    Ellensburg, WA
    [ QUOTE ]
    Here's the lowdown on gears.....

    When you have a higher number, such as 4.11 or 4.56, that is refered to as a lower gear and when the number is lower such as a 3.42 or 3.73, it's refered to as a higher gear ratio. Don't ask, just the way it is.

    As for the meat of the subject, when you have a higher gear ratio (lower numerically) you will have a higher top speed, but your torque will suffer and will not get up to speed as good.

    The opposite is true for the lower (higher numberically) gear ratios. You will get off the line faster, but your top speed suffers. Not really applicable for us is the top speed facet, but with the lower gear ratio, the engine and transmission works less and in low speed situations such as rockcrawling, this is what you want.

    Tires affect the overall ratio also. A taller tire will give you a higher gear; whereas a shorter tire will give you a smaller gear ratio.

    Example. I currently run a 3.73 gear in my rearend with 35" tires. The 3.73 number is in effect a 3.4something gear and it's now a higher gear. My torque has suffered with this change. If I want the 3.73 back, I would have to change to a 4.11.

    Did that confuse you enough? /forums/images/graemlins/thumb.gif

    [/ QUOTE ]
    You don't actually lose torque. Torque is produced by your engine which has nothing to do w/ your gears. It just feels like you have less torque because your EFFECTIVE GEAR RATIO gets thrown way off when you run large tires on a tall gear
     
  14. sdavid

    sdavid 1/2 ton status

    Joined:
    Aug 5, 2002
    Posts:
    244
    Likes Received:
    0
    Location:
    Livingston, TX
    He might want to make sure that the front and the rear are going to match. Quick way to twist something up if they don't.
     
  15. Bubba Ray Boudreaux

    Bubba Ray Boudreaux 1 ton status

    Joined:
    Jan 21, 2001
    Posts:
    20,716
    Likes Received:
    2
    Location:
    Undisclosed Location
    [ QUOTE ]
    You don't actually lose torque. Torque is produced by your engine which has nothing to do w/ your gears. It just feels like you have less torque because your EFFECTIVE GEAR RATIO gets thrown way off when you run large tires on a tall gear

    [/ QUOTE ]

    Could I use that on my wife the next time I piss her off?

    "But honey, I didn't make you mad that much, it just feels like your that mad."
    /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif

    Seriously though, since I've forgotten all my learning. Torque is the force that is used to get work done, and horsepower is the speed at which it gets done. Am I correct?
     

Share This Page