I just bought my first new used truck. A 2002 GMC Sierra 2500HD crew cab 4x4 duramax/ally. I found it by sheer luck at a dealer while browsing an ext cab model I really wasn't interested in. After having it inspected, and all the usual stuff one does with a used rig, I bought it. After I drove it home I deciphered the list of RPO codes in the glove compartment, and only then found that the truck LACKS code G80, "axle positraction limited slip". In my online shopping for a truck, I had decided that was an option I wanted, but I seriously doubt that I would have turned down the truck once I found it just because it lacked that feature. My question is: in a truck equipped such as mine is, is it logical for it NOT to include the limited slip rear axle? I'm no truck expert at all. Is there something in the combination of diesel, allison, and 4x4, for example, that makes it unnecessary to ALSO include the limited slip rear axle? I guess, finally, my question is, since I plan to tow a travel trailer about 25% of the time, do I really need it after all?
Kinda odd for it not to hacve it, probably means it was a special order since the factory usually lumps it in with the Diesel package. If you're always on the road or fire road type stuff, you'll probably never notice. Marc
G80 is not really a "limited slip" but rather a positive "locker" that comes in and out when needed (hopefully). Also known as a "gov-lock", it's much like a spool when engaged, acts like open otherwise. My '02 CC DMax/Alli SWB 4x4 came with it, but it is an option so some did not. I'm glad I have it, and I feel it's been of value several times when in snow/ice or soft/muddy fields. However, I wouldn't consider it a deal breaker for an otherwise good deal. You should be able to find an axle or diff to swap without too much trouble, and the after market will likely step in soon (if not already) with options like a Detroit or others. Sorry, but that's about all I can offer.
My C3500 Dually with a 14BFF rear axle has a gov-loc. I'd rather have the open carrier so I could drop a detroit locker in it as it would be stronger than a gov-loc'ed 14BFF. waytogo If I ever blow up the gov-loc I'll swap in a detroit locker in a open carrier.
The new HD AM axle still does not have any after market support for lockers as far as I know, but then again I haven't really researched it lately. But the G80 in the HD axles is a fine choice for a multi-purpose "street" truck. Unlike the lighter 1/2 and 3/4 ton G80 versions, including the MD 14SF, the HD G80s (10.5 or 11.5 ring IIRC?) hold up very well in my experience. Nice manners most of the time, but when I open 'er up, it hooks up on both sides, unless I want to break 'em both loose that is... I've managed to "separate" 4 tire's tread from the carcass putting down around 750 ft/lbs of torque through that locked axle with no problems, and there are guys doing quarter mile runs every week end or hauling 30k hot-shot rigs with no problems that I've heard of to date. Anyway, as long as you don't run really big tires or do technical off-road stuff like rock crawling (where the potential for sudden lock-up can cause problems) they hold up fine and work well for a multi-purpose rig. When I have driven on ice it is much, MUCH better than either a Detroit or typical LS for finessing the ice and keeping things under control. But when traction is just not there and slippage is inevitable, the locker comes in, albeit a little more harshly than ideal for ice. <shrug> I gotta say that with out it on a particular elevated section of I40 in N Texas where I had to go *up* an on ramp covered with skating rink quality ice after fueling up, I probably would have joined the Z71, 4x4 Ram, and several FWD cars unable to make the grade on the side of the road. As it was, I pretty much just idled up it in 4WD (3 wheels pulling) and continued on my cross country odyssey. This is just commentary on the G80 "locker" and is not meant to say you NEED a locker. I've found it useful, but that is in limited cases and often in situations that I could have also gotten through without it (although maybe it would have been more trouble).
I hear you Russ. My Dually is funny as most people with Duallys seam to have a Dana rear axle. And I haven't had any problems with the gov-loc in my 14BFF but if I did blow it up then I'd switch to a DL.
