Roddy1

Hey guys we just received a new fleet of work trucks. 2500HD, 6.0 Vortec 4x4's. Im wondering if this truck has a limited slip rear? We use them in mud and snow, primitive roads... they got us stripped down trucks, with highway tires, no CD players, armstrong windows....its sad that the general even ships out vehicles like this..its 2010 not 1985.

Anyway is there a door code i can check?

Thanks, wanna know how soon to be prepared to get stuck.

s34n

check in the glovebox for rpo code g80.

therewolf

Hi Roddy1,

Welcome to the Chevy forums.

What you've got, more'n likely, is the 4l80e tranny connected to standard 410 differentials.

RPO code GT5(also GT8) is for non-posi 410 gears.

You'll probably find you have E-rated 80PSI truck radial tires. Yes, they're highway tread, but brawny as they come.

Roddy1

Hi thanks for the fast response's!

Its is a GT5 RPO code. - Open Diff.

Why do alot of the heavy duty trucks, like GM's and Ford's come with open diff's...where the small trucks like tacoma's or ranger's have limited slips or lockers standard?

Im concerned now for the winter in deep snow. I know we are getting new tires and chains....but still open diffs are gonna be an issue

s34n

i agree because with an open diff only one wheel will do the driving while the other one is stationary in the snow. are you allowed to do any mods to the truck?

therewolf

Yeah, I hate to fly in the face of reason, guys, but these are some rather large trucks, with beefy drivetrains.

I'm not bragging on GM quality or strength particularly, but I'd like to point out that you're dealing with 7000 Lb. trucks, 340+ HP engines, 410 rears, and very stiff 30" tires.

Now I'm not going to be sarcastic and say "call me the first time you get stuck" and get stuck you very well may, but exactly how often do you go offroad in the name of your job? Because with the size, torque, weight, and horsepower of the vehicles involved, posi rears could make for some very miserable trucks on the tarmac. Bear in mind they have a poor turning radius,(Worst in it's class-OOPS where'd THAT factoid come from?) and with the Z85 HD suspension(chassis package-high payload-firm ride) you'd see a lot of egregious axle hop if you were to add a posi rear into the mix. I only go offroad when camping and fishing, but I've never gotten stuck in the dirt with my 2500HD.

In any event, I'd likely be more inclined to try to get the boss to see the light of reason in the direction of installing a heavy-duty winch to deal with getting stuck, in the event you do have this problem. The cost will be less for the winches, in all likelihood, and you could help pull each other out. You must consider that the relatively narrow 245-75-16 OEM Highway Radials would eat themselves into soft dirt or mud up to the axles even faster with a posi-rear, given the engine power and differential torque you already possess. You may already have noticed you break traction fairly quickly on wet asphalt or when cornering.

This winter I went through the snowstorms in my area, and short of the time I carelessly plowed the truck full-on into high snow drifts, I didn't get stuck once, even then with a little shoveling and rocking I got it out myself. What kind of snow do you get in your area?

Roddy1

I go on road for 3 or so hours on monday and friday...... Ill spend the better part of the week travelling primitive unmaintained roads, no roads, utility line and gas line roads...roads isnt the right word.

I work up past the 60th parrallel in the arctic circle of the Canadian northwest territories. We get horizontal snow storms, -50 Celcius, -60 windchills, I couldnt describe the snow fall in inches though..sometimes the drifts are as high as houses.... I do have a Quad for the tricky area's and in the winter a snowmobile.... or snow shoes....

therewolf

OK, now bearing in mind that your situation particularly is a little more severe than most, I just want to say that as long as I've stayed on anything even resembling a road, I've never gotten my 2500HD stuck. So I think it's safe to say these vehicles don't particularly lend themselves to getting stuck. My experience has been they're a pretty stable platform, all in all. The HDs usually have a factory 2 inch body lift which helps keep them from getting " lost in the sauce".(RPO-HVY-)

But I certainly can't disagree with you that you may have difficulties.

Has it been your experience that other vehicles up there do better with a posi axle or two?