IMHO its not good on the truck, this is why its call part time 4wd, not designed for full time use, as is on dry hard surfaces.

I have done my fair share of driving on snow/ice roads, in fact thats what I learned to drive on 16 years ago. Next time your out in a storm look in the ditch, what is the common denominator among most of the rigs? 4wd, because people think it does much more than it does. 99% of what it does is help you get going, a little, I mean LITTLE help on steering, but thats only if your steering beyond traction limits and your pushing the front end, and a little in braking because it requires you lock a front to lock both rears (open diff). This helps you brake and maintain lateral stability, same reason an open diff, or helical LSD, is the best on snow.. lateral traction.

While its a little harder to bring the rear around in 4wd, its not that hard... and if your on a slick enough surface it wont matter in the least.

Braking can be done on slick roads, its all about pedal pressure... I also have found that mild down shifting, in 4wd, will help your braking ability, but try it in 2wd and you will swap ends.

Up to 3% difference is acceptable on f/r diff ratios, for offroad use.. try it on a dry hard surface... if your lucky your tires will break loose and undo the bind before the xcase housing lets loose... or a U-joint on weaker front axles.

Yes the equasion I showed would only be relevant if you had lockers front and rear... but it shows the difference that the smallest amount of differences in tires makes... Yes if you were to drive in a perfectly straight line AND, with open diffs, one front tire and one rear tire had the EXACT same circumference (rev/mile) you would not induce a bind... but show me a place you can do that, the crown of roads is enough to require you to have to make adjustments in the steering wheel.

I generally am the one of the fastest guys driving on snow and ice, and I am rarely in 4wd. So to expand upon my "stupid" comment, if your going much above 35 to 40 and you think 4wd is helping you then yes its stupid.. it does nothing at those speeds, let alone 60+... I also was calling the act stupid, which does not imply I was calling you stupid... I do stupid things every day, as everyone does...

And there is NO tq differential between the front and rear axle in PT 4wd, thats what FT 4wd does, which allows use on dry hard surfaces.

The fact is that your 4 tires all have different circumferences, your front and rear axles receive the SAME tq, and same rotations... so the differences in your tires create a bind, on slick surfaces a tire slips and the bind is lost, on hard surfaces the tire generally cannont slip, unless you are in a tight turn or have a large amount of power applied... binding will induce. It is generally felt in the transfer case shifter, I have even seen enough binding from dirt road driving to make it hard to shift out of 4wd. High speed driving makes this worse as its harder for the bind to reduce from tire slippage.... When I used to wheel my toyota rock crawlers I would shift out of 4wd all the time to relieve the stress on the xcase and CV's.. some of the guys I would wheel with wouldn't, and when they tried to go back to 2wd they had a very hard time shifting out of 4wd... and this was all on low traction surfaces....



Anyways.. .back to the OP... your driveline can handle high speed 4wd use.. in fact everything spins all the time anyhow... but you will get no benefit from it, and if the surface has too much traction you can hurt the drivetrain, but thats from binding and not from speed.

 

Roads are wet down here alot and if its slippery 4hi it goes and it stays their. It also comes in handy at the track 0-110mph and no problems here.

 

I agree, however, you're not taking into account that even on dry surfaces, the circumference of each tire is dynamic. It changes constantly as you drive, hit bumps, expansion joints etc. It's the dynamic nature of the tire/road interface that will negate the binding effect that you describe. Even on a dry surface, there is tire slippage, however small, otherwise tires would not wear as quickly as they do. Most of this slippage being within the lugs themselves.

Besides the fact that I have zero concern about the NV271 transfer case in my truck being damaged or failing. The NV271 is rated to handle almost 8000 lb-ft of torque. Like I said, when I am shifting in and out of 4wd at highway speeds, it's smooth and easy. I would expect a U-joint or axle shaft to fail long before the T-Case puked.

I'll agree to disagree. You haven't given meany reason to change the way I drive, and every region is different than others. When it is 5 degrees out with strong crosswinds, sporadically wet roads, blowing snow and light drifting. I'll leave it in 4wd. If I am in 2wd and the rear end kicks out, my options are limited to regain control. When I am in 4wd, the chances of the rear end kicking out are greatly reduced, especially with an 1100 lb motor sitting right over the axle, and if it does, the opportunity to gain control is much greater.

I also agree that it is better to drive 2wd on dry pavement. The conditions I drove that day were intermittently dry, wet snow covered ,etc.

I see those 4wd's in the ditch. What makes you think they were in 4wd and not 2hi?

 

Yeah, I agree to disagree.. in those windy conditions where it takes hp to keep moving then 4wd will help you go straight due to the motor, like we have both said... have to break one axle loose to break the other loose. Time where hp to keep moving excceds traction are typically rare, even on snow.. it the hp required to accelerate that usually gets you... where I usually throw it in 4, and slow down. One thing nice about these trucks is they are LONG, and that really reduces the wrap rate when the *** kicks out.

I would say the 4wd were in 4hi, simply because "its 4wd man, I can do anything"

I have done 300-400 mile days where I am in the conditions like you listed, dry, compact, ice, etc... and I have driven 65-70... but I was generally in 2wd.. there were 50 mile stretches where the road was completely covered and I would go into 4, but I would also slow to about 45 max... so yes conditions do vary... but I still feel 60+ in 4wd is too fast for the conditions...


That doesn't induce horrible binding? Driving around here with an inch or two of fresh snow thats not compacted creates such horrible binding and popping around here that I and constantly in and out of 4 due to the binding... The weight of the motor really increases front traction and reduces slippage.

 

ah64id,

Why did you spend the extra $ for a 4wd? Just to get moving?

Nick

 

I drive in 4X4 all the time in winter as fast as 100 mph and have had zero problems. Regular highway speed of 80 mph in 4X4 all the time even when it alternates from dry patches to slippery sections. It makes it far easier to recover from slides by using the power to pull out of a slide. I have never broken anything doing this and did have 672K Km on one of my trucks doing this to it the whole time.

 

I drove a '74 Chevy 3/4 ton 4WD around 300 miles on dry pavement at speeds up to 80 MPH while it was stuck in 4HI and, outside of the front wheel wobble while going around corners, I couldn't tell that it was locked in. No damage. The truck's owner had pulled the same stunt once before I did it. Now, I wouldn't recommend doing that, but, I think you can get away with it as long as you don't try leaving it in 4HI on pavement for the life of the vehicle.

 

Personally, I think you have other mechanical problems if you get that kind of binding in those conditions. The only thing I have experienced even close to that is wheel hop in deep snow with fresh BFG AT's. Other than parking lot turns or tight corners, I have never experienced any binding in a 4wd. I have owned 4 different trucks with the NV271/273 T-case in the last 8 years.

This is my last post on this thread, so I have to say this. 4wd is for more than getting you going. I live on a pretty good hill. If there is packed snow on it at all, 4wd is mandatory. I can be doing 25mph at the bottom of the hill and hit a stand still with the motor at the same RPM it was at 25mph. No matter what I do to make it, I have to be in 4wd to maintain momentum and directional stability.

 

Happens on both mine and my dads trucks... its normal, but I notice it more in these trucks that others due to the super heavy front end... It just has a harder time slipping with the weight, even with these crappy OEM tires.


And I use my 4wd all the time, but the simple fact is that 99% of the time 4wd is not as good as people think it is, now I am not saying I dont use it, abuse it, but its not as good at speed as people think it is. Does it help yet, does it help as much as most think, no.

 

I have never had any problems and use my 4x4 on dry pavement all the time when racing 0-110+mph wot no probs of any kind

I use 4x4 in the rain on oil infested freeways and roads

never shift in or out of 4x4 at speeds over 50mph

maybe I been lucky, but sure glad I have elect shift 4x4 on my truck cause I use it often & love it !

I used 4x4 on snow and rain for 300 miles + ave 70 mph on an 880 mile trip a week ago and ave 18.66 mpg ave 880 miles with speeds varied between 45-100 mph

over 300 miles of the trip in 4x4 mostly over 70 mph ......

 

That was fun...I wonder if sallyman1 got his answer?

Cya

 

How do you know what people think? Are you a mind reader? The problem I've seen most is people not using 4wd until they get stuck, then using it trying to get un-stuck, when a lot of the time, it's too late. In low traction, off-road situations. I put it in 4x4 as soon as I leave the pavement. I've also seen the same problem an the pavement; people don't engage 4wd soon enough on slick roads. They rate until they start slipping, and if their not paying close enough attention, they switch ends; being in 4wd could have prevented this. I attribute both of these problems to the conception that using 4wd is bad for the vehicle. I disagree with this; you paid extra for it, you use extra fuel because of it's weight, so use it.

Nick

 

amen brother !

 

Because over the years it is what I have observed, both online and in person.

And I do use my 4wd, all the time... I am not saying don't use it... I am saying there are times when people use it, and put too much faith in it... I am big into 4wheeling, rock crawling, etc.... I know 4wds, and what they can and can't do...

I do plenty of hi speed driving on snow/ice, I have many years experience with it, I have never said to slow down on snow/ice... what I have said is if you think your 4wd i really helping at high speeds then your wrong... there are a few instances where it helps, which do occur more in these trucks, but they are still not the norm.

You can do what you want with your truck... just don't get me or my family into a wreck because of over confidence in 4wd.

 

Then stay out of Oregon; and don't wreck me because you aren't in 4wd, because of your over-confidence in your driving abilities.

Nick