Standard 2wd - Should I upgrade to LSD, Posi, Locker?

Discussion in 'GM Powertrain' started by Highmarker, Oct 11, 2011.

  1. Highmarker

    Highmarker Rockstar

    Ok, hear me out first before you go posting about limited slip differentials and such.

    I have an '03 Silverado 2500HD that is 2wd and does not have the G80 posi-traction limited slip differential. I live in Utah where winters can be down right brutal some times. I am wondering if installing an aftermarket LSD, posi, or even a locker would be beneficial. I don't go "off-roading" or anything like that (I would have bought a 4wd for that). I just want control when I am going down the highway in a snow storm. Occasionally I will pull a 6-7,000 lb travel trailer with my truck. So I don't what something that will burn up. My father is a mechanic and has been for over 40 years and he tells me of people who come into his shop and want the G80 removed from their truck because it keeps burning up. I have looked at other Eaton and American Axle differentials, but they all seem to be the same with exception to the electronic or air lockers where they are manual. I have a friend who says that the automatic engagement and disengagement of the LSD is somewhat frightening when it kicks in going down the highway. You are never sure when it going to engage/disengage and when it is not.

    Is it worth it? Thanks in advance.
     
  2. Greg84

    Greg84 Rockstar 100 Posts

    If your friend has the factory g80 locker engaging when he's going down the highway there's something wrong, they're not supposed to engage over 25mph.. The only time I notice it engaging is when I'm turning a corner in the snow or rain and accelerating, like off of a stop light or stop sign and the back end will try to kick out. If you're having problems getting moving in winter, it'll help. Its still not going to be anything like 4wd, but better than nothing.
     
  3. MrShorty

    MrShorty Epic Member Staff Member 5+ Years 1000 Posts

    In my opinion, you get very little benefit for the expense in terms of "routine" snow driving like you're describing. In fact, in terms of "control" I think you have better control with an open diff. Two reasons:

    1) Understeer. With any "traction" differential, you get some increased understeer. It is particular bad with non-selectable lockers (those are the ones that "kick in" on the highway like you described). I've locked my ARB a few times in the snow and scared myself with how bad the understeer was. With a locker, the physics at each wheel has to decide what will slip first when turning -- the inside rear wheel, or the front wheels. If all 4 wheels have equal traction, then they will all slip equally causing your turns to be much less responsive. A decent limited slip (like a clutch type or geared type limited slip), isn't as bad as a locker.

    2) Fish tailing and "kick out". Because lockers and limited slips don't want to let one rear wheel spin without the other, you increase the chance of fishtailing and, worse, having the rear end "kick out" on corners. As before, this will be most noticeable with lockers rather than limited slips. With an open diff, one wheel can spin, while the other doesn't. The non-spinning wheel actually has better traction which helps the rear end track straight. When both wheels spin, then the back end will go the direction of least resistance, which might be sideways.

    Another thing to remember is that aftermarket differentials like we're talking about only help in the "go" department -- they make no difference in terms of stopping power. Think of those "close calls" you've had when driving in the snow and, if your experience is like mine, most of them are related to not being able to stop or not being able to turn. Rebuilding the differential doesn't help in those situations. Rebuilding the diff will only help in those situations where you are accelerating and one wheel has significantly better traction than the other.

    For routine snow driving, I would suggest you spend your money on good snow tires (probably with studs), maybe a set of chains, rather than rebuilding the differential. Good tires not only help with traction for going, but also improve stopping and steering traction, which is what improves your control.

    My 2 cents worth.
     
  4. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    ARB makes a air-locker for your 2500. I like the air-lockers because its the best of both worlds with just the touch of a button.
     
  5. Highmarker

    Highmarker Rockstar

    Thank you all for the info. This is very helpful.
     
  6. dpeter

    dpeter Rockstar 4 Years 500 Posts

    MrShorty gives realy good advice and valid comparisons. If you're already moving, an open differential is the way to go for control for the reasons MrShorty has stated. I would add this to the pros of open diffs. ... If you are putting much power to the ground to maintain speed and you come acoss a slick spot such as drifting snow, iced bridges, shaded spots, etc. then the chances of both wheels spinning with a posi trac or locker are great and you will loose directional stability. Drift a little and then hit dry pavement and suddenly you're shooting for the ditch at the precise angle of that drift.
    These are the resaons I like the G80 locker. Yea, it may be a little clunky but it will get you going and then give you back the control of the open diff.
     
  7. hotrodking86

    hotrodking86 Rockstar 100 Posts

    My one regret with my truck is that I did not get the 4x4. But at the time I thought about the price and what not, but now I want to go off roading. I guess I could always just buy an older truck with 4x4 and take that out, this way I won't ruin my daily driver.
     
  8. Sierraowner5.3

    Sierraowner5.3 Rockstar 3 Years 1000 Posts

    get a late 80s k1500. cheap and they have the 350 so got lots of room to grow power.

    as far as the OP, a buddy of mine has a detroit tru trac in his truck, he has good luck with it (works like the G80)

    cheapest solution is to get a good set of snow tires and do some rear end weighting to get the power to the ground without slipping. 200 lbs made a world of diff in my half ton.

    Alex
     
  9. Highmarker

    Highmarker Rockstar

    I have a good set of tires on it now. I think for $50 - $100 bucks I can get a good set of chains. I think with chains it is a little a Murphy's Law. If I don't have them - I will need them. If I have them - I won't need them. I better get them.
     

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