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Discussion in 'Chevy Trucks' started by roja, Feb 14, 2001.

  1. roja

    roja Junior Member
    Messages: 5

    can you guys help with some questions please?
    do any or some or all older (60's - 80's)chevy pickups have posi-traction? how can you tell?
    how inferior would a truck with posi be to a 4 wheel drive truck.
    i'm shopping for a truck and am under the impression that a 4 wheel drive is actually really a 2 wheel drive...which may be equivalent to posi...i already know that i'm a complete idiot. that being said, i am still curious.
    thankyou, roj
  2. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    a 2wd truck with posi is not even close to a 4wd without,in most cases.with an open diff.,all 4 tires are driven,but the tires only have a much traction as the tire with the least traction,kinda like a chain,only as strong as the weakest link.If one rear tire is on glare ice,the other on grooved concrete-all the power will seem to transfer to the tire on ice-since it is the weakest link-the same amount of torque is on the other tire too,but since its on concrete,it wont spin.id take a 4wd with open diffs any day over a 2wd with a posi unit.
  3. roja

    roja Junior Member
    Messages: 5

    nice lawn john

    if thats a green in the background. i'm envious, although with my hook i'd spend a lot of times in those woods...
    i appreciate your explanation and realize that a pickup is light in the rear, but with a standard 4 wheel dr. it sounds like only 2 wheels are providing driving power. how is that better?
  4. 75

    75 PlowSite.com Addict
    Messages: 1,382

    A couple of reasons the 4x4 will outperform a 2wd in slippery conditions is that although the back end is light, the front drive axle has plenty of weight right above it. Another reason is that one of the two axles will often be on good footing. An example is plowing snow, when stacking a pile the front wheels may get into some soft stuff but the back usually has a decent bite. Having said this, when you get a 4x4 stuck (and it happens all the time!) you are r-e-a-l-l-y stuck. I know posi rears were offered in GM pickups but I don't know how to go about identifying one or what years they were offered. Whether you go with 4x4 or 2wd depends a lot on what you plan to do with your truck. If you plan to plow snow or go off road with it, 4x4 is the way to go. If it's going to be on pavement all the time, 2wd might be your better bet.

    1975 GMC C-35
  5. mike reeh

    mike reeh Senior Member
    Messages: 114

    Dont ever let anyone tell you that posi 2WD will go anywhere a 4WD will go.. that is complete and 100% B.S. Ive had people try to get me to beleive it.. its a joke

    as for the whole 4wd drive- only two wheels are driving thing, if you are trying to understand it in terms of theory, you'll never understand... the theory and real life experience are two different things... I dont even know how I would go about explaining it, its a huge concept to grasp, you just gotta experience it, like i said. the difference between 2wd and 4wd in mud/sand/snow are like night and day.. the diff between 4wd non posi and 4wd posi, are like dusk and dark .. if that makes sense :) in other words there is really not a huge difference, especially on a daily driver.. if you're building and off-road machine, well thats different..

    if you have ever watched any open diff vehicles play in the mud, you will notice that both wheels usually do spin. even on concrete/dirt/etc... its a vast difference in terrain between the two drive wheels that really shows the weakness of an open diff.. IE if you pull off to the side of the road on a soft shoulder and one wheel is on dry, clean pavement..

  6. thelawnguy

    thelawnguy PlowSite.com Addict
    Messages: 1,011

    The code on the option plate/sticker for posi or gov-lok rear in GM corp products is G80. Or jack up both rear wheels, with the e brake off and the trans in P or 1st turn one wheel the other will turn in same direction for posi, opposite direction for open diff.
  7. roja

    roja Junior Member
    Messages: 5

    thanks lawnguy