I would like to know if this model can be considered as extremely reliable on offroad use, tracks dunes river cross, ice and deep snow. Temperature from -40 degrees C to 60 degrees C.
They're pretty tough trucks so long as you keep up on the maintenance.
Can it carry offroad 1.5 to 2 tonnes of equipment?
Dunno- are you talking about pulling a trailer or hauling it in the bed? If in the bed, then I'd recommend a set of helper springs, since the trucks are rated to 1.25 tons. A set of 2500 pound helpers would bump that to 2.5 and you'd be fine. For loads that heavy, though, you may want to consider adding more power, depending on the terrain you're in. At the very least, you'll want something better than the 2.48 first gear of the TH400, at least you'll want something better if you actually want to be able to get going uphill in mud or sand with that kind of load.
What kind of upgrades this truck require to fit the job? Do the frame need to be reinforced?
Frame should be fine, but for serious offroad use you'll want to beef up the steering. If it was me building up the truck, I'd also want to replace the TH400 trans with anything that doesn't have such crappy ratios as well.
Do parts are easy to find? Do the powertrain can handle hard and long work in soft sand and burning rocks?
Parts are easy to find around here, because they're common, off the shelf Chevrolet parts. I have no idea what the Chevrolet parts situation is like in your area, but it should be easy enough for you to ask around for Chevy K30, base model, 6.2L (VIN J) diesel parts. The military-specific parts, though, may be tough to come by, like the alternators and the starter. I mean, you can get them, but if you need them fast, it'll take even longer and/or be way more expensive than it is for us here. You may want to consider a 12v conversion on the truck so that everything is common and off the shelf. There are only a few hard to get, non-civilian parts, but when you lose a starter, it sucks.
The 6.2 diesel should be fine, the Dana 60 and 14 bolt rear should be fine. The Detroit Locker in the rear should get you out of even the nastiest situations.
What would be the clearance bellow axles with 35 or 36" tires?
No idea, but I suppose you could look up the factory ground clearance (stock tires are ~32") and then add to that figure whatever the new tires would add.
Is it possible to fit Torsen or truetrac differentials in both dana 60 axles?
i am a big fan of these
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Why on earth would you want a Torsen differential in ANY off road situation, much less an extreme one like some of the things you seem to be describing? I mean, you *do* realize that a Torsen is worthless if one wheel is off the ground or otherwise has no traction, right?
That said, yes, it's possible to fit various types of limited slips and lockers to a Dana 60. Personally I'd go for an air or electric locker so that it doesn't screw up your steering (you can leave it open) and you have full locking action when needed.
And now, what would be the gas millage for this truck, with 35 to 37" tires, and a 4" lift. On roads..90/100km/h and highway 110/120km/h and in sand?
120km/h (roughly 75mph for those too lazy to convert) is a lofty goal with the 4.56 gears. With a non-overdrive trans and 37" tires, the top speed (redline in third) is about 82mph, so the motor will be spinning pretty damn fast. Not recommended for long periods if it can be avoided. Yes, the M1009s have 3.08 gears and can do highway speeds even with the stock tires without the motor screaming, but that's not really relevant, because for hauling heavy loads over nasty terrain, the 1009 is pretty much out of the question. An overdrive transmission would help with the engine speed at highway cruise.
As far as fuel consumption, I've found that the usage of the truck doesn't really matter, it's always around 15 miles/gallon. Around town the fuel economy sucks because you're hauling around 6000 pounds of steel even without any load, and on the highway you lose because you have the frontal area of a small building. Off-road fuel economy is nearly impossible to figure out, since the speeds involved are so low. I would recommend adding the second fuel tank, though. The stock 20-gallon unit provides lackluster range at best. It's fine when just driving around- but you whouldn't want to be stuck in the middle of nowhere low on fuel.
Oh, one more thing
, i have seen a couple of post ragarding the the glow plug for pre heating ..is it a weakness on this model?
Glow plugs are fine, except when they burn out. Burnt out glow plugs shouldn't come as a surprise on an older truck, though. What most people complain about is the stock automatic controller system going bad, which then fails to properly cycle the plugs. I just ripped out the stock system and replaced it with a manual button that I hold to cycle the plugs on. Some people complain that the manual plugs are somehow inferior to the automatic systems, but I've yet to figure out why. The glow plugs don't know whether they're being actuated manually or automatically, so I'm guessing it's user error.
As for your other questions:
The trans is cooled fine for most peoples' use. I doubt you'd be too hard on it, but trans coolers are cheap. Just make sure you don't overcool the trans in the -40 degree weather you're talking about.
See my earlier comments regarding front limited slip differentials. The M1028 has a front limited slip.
Banks turbo kit is a good one, or you can add the system from a 6.5L truck.
Rear disc conversion would be nice, but not really necessary. I think it would be cool, and not all that difficult, but it's just not worth it to me. The stock system hasn't let me down yet.
The only issue with lifting the truck is the load capacity. Most lift springs aren't designed to carry heavy loads, if anything, they're designed to compress more so that the wheels stay on the ground better. Just be careful in your selection.
I've got 35" tires on the stock suspension (although I have helpers in the back which add a good bit of clearance) with minor front fender trimming. AJMBLAZER has 38s on his with 1" of front lift and fender trimming, but they're narrow 38s.
If you're seriously going to be using the truck off road, and hauling 1-2 tons off road, there is no way in hell you want to cut into the gearing. If anything, you may want to go deeper, but I think the 4.56 combined with the NP208's low range should be fine. It's the 2.48 first gear that sucks.
People have installed 700s. I don't know if it fits well with your use, although a built 700 should be able to handle it. Modification is minimal, and the gear ratios are better, but there are those who have problems with them. If you were using the truck primarily on road without the type of extreme situations I'm thinking up, I'd say it'd be just fine.
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