I know you are not supposed to drive around on dry pavement in 4WD, which I don't do. But what about if you are driving on a mountain road, which is curvy, but has occasional icy patches and you want to be in 4WD for safety? Or when driving in snow, when the wheels will not be slipping most of the time? How about a dirt road, or severe rain conditions? You may want to be in 4WD for these situations even though most of the driving will not be on the ice, mud, or whatever. What is the risk of driving in 4WD on pavement? I have a manual transfer case and hubs. What if I have the hubs locked and the transfer case in 2WD? Then I can shift into 4WD on the fly. Is that bad? I used to have a Dodge Ramcharger that was in 4WD all the time. Nothing ever happened to it, except you could feel it when making sharp turns. What is the point of having 4WD if the only time you can use it is if you get stuck in a mud bog or something?

 

You should be able to just leave the hubs locked and shift in and out of 4wd as needed. With the hubs locked in, you can shift into 4 hi on the fly. As long as your not on a high traction surface such as dry pavement, where your drivetrain would bind up and possibly break something, you should be able to use 4x4 when you feel you need it. Leaving it locked in and in 2wd won't hurt a thing except for a little more wear on the frontend and slightly lower gas mileage.

 

brown 4x4's right. When living in snow country, I'd lock my hubs when when winter weather started and never unlock them until late spring, after the snow turned into mud and that dried out.

 

You can drive in 4HI on pretty much anything BUT dry pavement. The risk (on dry pavement) is that front and rear wheels may not turn at the same rate, even when driving straight, because of things like slightly different tire pressure, tire wear, blah blah. But the t-case forces both driveshafts to turn at the same rate. So, there's a possibility that much 4HI driving on dry pavement will cause undue t-case wear. The potential difference in revolutions from front axle to rear axle are very small however; thus, wet pavement or dirt roads allow plenty of slippage for the drivetrain to release any potential bind. Clear as mud?
As a side note, I once knew a guy who's son drove their pickup from Colo to Fla and back in 4HI (the kid didn't know) and it pretty much destroyed the t-case.
Also, most AWD vehicles have some sort of a center differential (in the t-case if so equipped) to prevent the above-mentioned problems - but I'll keep true 4WD in my trucks and take AWD in my cars thank you very much!

 

When it is snowing out and/or snow conditions I always keep the hubs locked so I can shift into 4H when needed.If you're driving over snow-covered roads with a few icy spots here and there keepingyourhubslocked so you can shift into 4H is a good idea.Now,driving on dry pavement in 4H is not a good idea.You're putting excessive wear on the hubs,T-case,etc.Driving through water you can be in 4H,or 4L range,but if the water submerges the hubs,you might want to service them.I'd only use 4L in deep snow,or when "crawling" off-road.In 4L range the vehicle will really dig in.NOTHING is good on ice!!! I (almost) learned the hard way.Back in '94,we really had a bad Winter here in the Northeast.We had many ice storms.One morning,I decided to take my Dad's '89 Bronco to work,and it was really bad outside."I have 4WD,so I'll be okay".Let's just say both the Bronco&I were fortunate that Friday morning...no damage to either of us,but that was one ride I don't wish to repeat!!!I was only going like 20m.p.h.,too.Starting sliding,then ,oh, about three three-sixties later,we ended up hitting a curb(actually we went over it....)-on the opposite side of the road.SCARY feeling,let me tell you.I did everything right,except one thing:I thought I 'd be okay on ice.If it is really icy out?Stay home,it isn't worth the risk.

 

Thanks for all the feedback. This information is very useful. I didn't have to worry about this in Florida. I am keeping my hubs unlocked, but if severe weather comes I am going to lock them before setting out so I can shift into 4WD on the fly. Another question: Is there a maximum speed that I can shift into 4WD on the fly at? Or a recommended one?

 

Oh yeah, I know about the ice too. 4WD on ice just means four tires spinning around instead of two. I was living in Seattle in the early 90's and there was a blizzard, and the roads iced up for a couple of weeks. I had a '66 F100 2WD with three on the tree, and as soon as I let the clutch out it spun into a ditch. I remember removing my spilled coffee mug and all the spilled coffee in one piece after I had the truck pulled out! PS - as far as chains, do people put chains on all four wheels on a 4WD, or is just the rear sufficient?

 

I have two words for driving on ice: studded tires. I had a Jeep Wrangler when I lived in Montana, and that thing was very difficult to keep on the road when it snowed. I had a set of studded tires put on for the winter, and that was a serious improvement. I rarely needed 4WD from then on.

 

 

You can shift into 4HI at any hiway speed (or lack thereof) you choose. You can leave the hubs locked all you want. You can shift into 4HI even if the hubs are not locked, it just won't do you any good :-) These systems are relatively simple, it's hard to hurt anything - and don't worry, it won't even think about going into 4lo until under 3mph, and then only if you REALLY tug on the lever (I did this once as a teenager), but you should always be at a full stop before shifting to 4lo.
As for chains, it's your preference, altho I once had a hard time explaining to my boss at the local ski area why one chain (it was all we could find) would do NO good on a single wheel w/an open diff LOL!

 

To shift into 4H if the hubs are locked already,I wouldn't try it above 35 m.p.h.I have friends who say it is safe to do so even if you're going 50-55 m.p.h. I wouldn't even suggest driving in 4WD above 50 m.p.h. Remember,it is best to slow down for unsafe driving conditions.Just because you can travel at a quicker pace ,doesn't mean the vehicles around you can.Vehicle control is another issue.As for studded tires,that is a good idea,and is better on icy roads,but other vehicles may not have them,so you could still end up in trouble.You may be able to go and stop alright,but it doesn't mean the traffic around you can....and in some states,the use of studded snow tires is illegal.I think here in Pennsylvania they are legal,but only during certain months.