Gear Ratio

Discussion in 'GMC Truck Forum' started by Donny, Mar 12, 2017.

  1. Donny

    Donny Full Member

    Joined:
    Jan 9, 2015
    Messages:
    69
    Likes Received:
    88
    Trophy Points:
    18
    Location:
    Texas
    I have had it in 4wheel drive a few times, why?
     
    MrMarty51 likes this.
  2. Donny

    Donny Full Member

    Joined:
    Jan 9, 2015
    Messages:
    69
    Likes Received:
    88
    Trophy Points:
    18
    Location:
    Texas
    I looked on you tube, the only talk about the rear gear ratio, nothing on the front one.
     
    MrMarty51 likes this.
  3. gmctrucks

    gmctrucks Full Member

    Joined:
    Nov 9, 2006
    Messages:
    9,058
    Likes Received:
    4,797
    Trophy Points:
    113
    Location:
    Houston,Texas
    One axle is going to turn faster than the other one so one axle will be making a chirping sound which in time will break something
     
    MrMarty51 likes this.
  4. Donny

    Donny Full Member

    Joined:
    Jan 9, 2015
    Messages:
    69
    Likes Received:
    88
    Trophy Points:
    18
    Location:
    Texas
    I have never heard a chirping sound, only thing I have noticed when I take it out of 4wheel drive, is sometimes I would get grinding somewhere in it.
     
    MrMarty51 likes this.
  5. Donny

    Donny Full Member

    Joined:
    Jan 9, 2015
    Messages:
    69
    Likes Received:
    88
    Trophy Points:
    18
    Location:
    Texas
    That is why I think the front gears is factory 3.42 while the rear had 3.73 in it
     
    gmctrucks and MrMarty51 like this.
  6. dirtrider73068

    dirtrider73068 Senior Moderator
    Staff Member

    Joined:
    Jul 14, 2011
    Messages:
    6,882
    Likes Received:
    4,393
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    dump trucker driver
    Location:
    Central Oklahoma
    In a 4x4 if the two diff gears are not the same one turns faster another slower puts alot of stress on the gears, will tear stuff up, transfer case gears, diff gears will wear them out if not bind up and bust the gears.
     
    gmctrucks and MrMarty51 like this.
  7. Donny

    Donny Full Member

    Joined:
    Jan 9, 2015
    Messages:
    69
    Likes Received:
    88
    Trophy Points:
    18
    Location:
    Texas
    Thats why I believe that my front is still 3.42, I bought the truck used 3yrs ago,my thought are that when they had truck redone after the accident it was in, they changed the rearend no knowing about the gears, lady owned it before me, gears do grind when I take it out of 4wheel drive, probably because of the 3.73 gears in the rearend, thats probably why the gears did bust,ring and pinion gear busted.Will go with the 3.42 gears in the rear also.
     
    gmctrucks and MrMarty51 like this.
  8. dirtrider73068

    dirtrider73068 Senior Moderator
    Staff Member

    Joined:
    Jul 14, 2011
    Messages:
    6,882
    Likes Received:
    4,393
    Trophy Points:
    113
    Gender:
    Male
    Occupation:
    dump trucker driver
    Location:
    Central Oklahoma
    If the front is 3.42 then the rears need to be the same.
     
    gmctrucks and MrMarty51 like this.
  9. MrMarty51

    MrMarty51 Full Member

    Joined:
    Aug 7, 2013
    Messages:
    7,404
    Likes Received:
    10,149
    Trophy Points:
    113
    Gender:
    Male
    If the rears is 3:42 and the front is 3:73, that thing will lock up and not move within twenty feet, or if You are getting on it, it will bust a gear, a U~Joint or any other number of given components.
    If Your vehicle did not bind to a stop then You gearing, front and rear, is the same.
    the old, real old 4X4s used to run 1 ratio higher in the front. if the rear was 4:10 then the front was 4:09. They did that so when slogging through the mud and snow, the front would be spinning and pulling faster than the rear end, for steering purposes. On thos old units, if You run them on hard pack for any distance whatever, they would bind up so bad that the would actually jump, and break things on the way there. It told right on the instructional sheet, on the dash or the sunvisor, to never run on solid surfaces when in four wheel drive.
    So, wioth that bit of knowledge, and those old units being just one number off, Your vehicle would not be able to move more than about fifteen or twenty feet without binding so bad that it would cease to move, unless You are really getting into the throttle, then something is going to bust.
     
    gmctrucks and leolkfrm like this.
  10. leolkfrm

    leolkfrm Full Member

    Joined:
    Mar 2, 2008
    Messages:
    12,741
    Likes Received:
    7,896
    Trophy Points:
    113
    Location:
    N.Y.
    the grinding may be the actuater in the front axle not disengaging properly, might be getting weak, had that problem with a 92
     
    gmctrucks likes this.

Share This Page