4 wheel drive questions

[herofan]

I assume some of you have a four wheel drive vehicle, so I'd like some clarification on something.

I have never owned a four wheel drive, but recently bought a Nissan Frontier 4x4. I've been reading and looking at things online and noticed the full-time and part-time four wheel drive.

I've read that part time four wheel drive shouldn't be driven on dry, paved roads. If you do, you may as well just drive it on to the salvage yard, because you've probably destroyed it. I know it doesn't make sense to engage it and drive 70 on the interstate in July; that wouldn't make sense; however, I've read that if you are on snow covered roads and come to a clear stretch of road, it would be best to switch back to 2 wheel drive. Really? Is four wheel drive really that delicate?

I've talked to a few people with four wheel drive, and they say they feel that is overboard. One guy said he once had a truck that in order to engage four wheel drive, he had to put it in neutral, engage the four wheel drive shift, put it in reverse and back up until he heard a click, and then he was ready to go forward in four wheel. He said once he put that in, it stayed until he was absolutely sure he was done with it. there was no in and out all the time. He said he would often drive for days in four wheel during a snow until the roads were fully clear.

So, what's the story on 4 wheel drive? Is it really that delicate?

 

[skyhightree1]

Most of my trucks are 4 wheel drive and I will tell you this my daily driver f150 has a turn know for 4wd and i wasnt paying attention thinking I was turning up the ac fan and drove home 45 miles in 4wd HI .. it still works fine no issues. I drive in 4wd high on asphalt whether its dry or snow on it and do not switch out. I have had a u joint break I took driveshaft out and put in 4wd high and drove home the 70 miles to get home in a truck. 4wd isnt as touchy as some think or maybe it is in certain manufacturers trucks. My wife has an AWD suv same as 4wd. What will destroy one is shifting while going too fast or trying to spin out on dry pavement. The only time i stop and put in neutral and roll back some is when shifting from 4wd Low to 2wd.

 

[M5farm]

I can switch mine to 4 high rolling on or off hwy. You only tear something up when on pavement and turn sharply while in 4wd. 4 low I engage it stopped and vehicle in neutral. You can hear the electronics engaging. I do the same to take it out of 4 low. The old Manuel 4wds you had to reverse vehicle when you disengaged 4wd and you could hear it unlock.

 

[Dega Moo]

My understanding: When turning or travelling around a curve the front left and front right wheels each travel, or roll, a different distance. With the vehicle locked into 4WD and these wheels being 'driven', the tires push or scuff across the tread of the tire trying to travel different distances while the tires 'roll' about the same distance. The rear tires get much less of that kind of action in any case because the wheels remain 'straight' and upright so scuffing tends to mostly be with the tire tread and not across the tread. Also, because the front end supports the engine there is generally more pressure on the front tires causing greater scuffing action there. Typically, in a curve brakes are applied or the vehicle decelerates forcing the front end down and weight into the front outside tire while taking weight off the rear tires, especially the inside rear. That's why the back end of a vehicle will tend to break out and slide to the outside of a curve around the outside front tire more often than the front end sliding in any conditions.

When using 4WD on slippery surfaces such as snow, ice and rain, that scuffing action is less abrasive to the tires and puts far less pressure on mechanical gears and wheels driving the front end. You can really feel it when trying to make a short turn at low speed on dry pavement in 4WD and then do the same on slick pavement or mud. Full time 4WD systems usually kick into 4WD when wheel slippage is recognized.

If you're travelling on a straight dry road you should be able to run in 4WD without issue because you're not pushing the tires sideways. A couple of decades ago it made sense to run 4WD on straight road once a month or so to ensure lube got into the lockouts and gearing.

 

[Jogeephus]

I've forgotten to disengage mine and didn't harm it but you sure can tell something is amiss when you make a turn. Apart from that, the best thing I can tell you about 4WD is its best reserved for reverse only. 95% of the time that is the only way I use mine.

 

[dun]

4 low on hard surfaces is hard on them. As somone mentioned they wheels are locked together at that point. 4 high it doesn;t hurt anything except your fuel mileage. Anyway that's the way Fords work.

 

[skyhightree1]

If you have someone that never wears a seatbelt you can fix them If you put your truck in 4WD low and then reverse.... stomp it after someone hits there noggin on that windshield they will never not put their seat belt on.

 

[herofan]

Thanks everyone for the clarification.

 

[highgrit]

Sky, why do you bring stuff like that up? I took the family on vacation in our motor home and my smart azz kid didn't need to put a seat belt on. So when here stood up I hit the brakes, needless to say he broke the windshield. But the wife was bringing me a cup of fresh brewed coffee and it ended up all over the place. Thanks for the memories buddy, how's the HORSE'S. btw

 

[ga.prime]

4WD is its best reserved for reverse only. 95% of the time that is the only way I use mine...

:lol2: That's right!

 

[skyhightree1]

Sky, why do you bring stuff like that up? I took the family on vacation in our motor home and my smart azz kid didn't need to put a seat belt on. So when here stood up I hit the brakes, needless to say he broke the windshield. But the wife was bringing me a cup of fresh brewed coffee and it ended up all over the place. Thanks for the memories buddy, how's the HORSE'S. btw

Hg you had to go there.. horses are a pita they try to run out the gate soon as you crack it open and bite my tractor tires

 

[wbvs58]

The problem with using 4wd on hard surfaces is that you get a differential in distance travelled between the front and rear axle when turning tight corners and consequently get this "windup" that can't be released because of the grip the tires have on the road. It has nothing to do with the difference in travel between the inside wheel and outside wheel on the same axle, the differential will equalise that, that is unless you have a diff lock engaged as well.
All wheel drive vehicles have a 3rd differential on the drive shaft between the front and rear axle to release this windup.
I have found with accidental engaging 4wd, driving on highways with relatively straight roads and gradual bends there is little problem however if manoevering around tight turns like roundabouts some very large forces will develop and it is very easy to do a lot of damage. It is obvious though, steering becomes very heavy and a lot of power is needed to continue going forward so if you use common sense when driving and don't force things you will usually circumvent problems.
Ken

 

[Brute 23]

There are different types of 4wd. A truck with locking solid axles will break some thing on asphalt.

The more modern 4wds have open differentials which turns one rear tire and the opposite front tire. It's much more forgiving.

There are options to lock the rear and the front stays open.

Some also have limited slip differentials that locks under light resistance but have a clutch like system to release instead of binding and breaking some thing.

Some 4wds have an option where it will engage itself when it senses a tire slipping.

I do not know of a modern vehicle that will lock up all the wheels. Read your vehicles specific owners manual to find out what you have. That will tell you how forgiving the 4wd system is.

 

[gimpyrancher]

4wd High driven on the highway isn't going to do anything except send a lot more profit to the oil companies. However, it's always entertained me when I see 4wd trucks that slid off the road in snowy conditions because they switched back to 2wd then drove to fast for the conditions.

Driving in 4wd will always cost fuel mileage because of the extra set of drive train you are turning. When I drive off road, I'm almost always in 2wd. When I start spinning tires, I put it in 4wd until I get out of trouble.

When I used to drive the Rubicon trail in my custom built Jeep, I was almost always in 4wd. But 2wd driving to and from the trail.

 

[backhoeboogie]

My Ford requires you to get out and lock in the front hubs. Then you can shift to 4 low or 4 high from inside. Not a problem. Kind of like it actually.

My GMC has a shift on the floor. Put it in park first. Never had it in 4 low.

Wouldn't put any of them in 4 low on pavement.

Been stuck too many times in my life to not have 4WD. Also tore up tires spinning them on rocks while dragging trailers uphill. That doesn't happen anymore now that I have gone 4WD. You slice a couple of tires and that fuel cost thing gets blown out of the water.

It all depends of what you intend to do with that truck. 16 and 17 miles per gallon out of that GMC aint bad at all for 4 WD. The Ford is a diesel one ton and it generally gets around 17 or 18 itself.

Can't imagine not having 4 WD any more.

 

[tom4018]

Agreed, everything I own is 4WD except the lawn mower. I like the manual shift and hubs.

 

[Nesikep]

In most full size trucks, there's no difference between 4 high and 4 low except for some additional gear reduction... Some Jeep Cherokees etc would have a 2 wheel drive mode, a 4 wheel assist mode, and then a 4 wheel lock mode, where the 4 wheel lock mode is the typical full size pickup 4WD mode.. in the "assist" mode, there's an additional differential in the transfer case...

Around here, I use 4wd while climbing or descending steep hills with a trailer, or in slippery conditions in the winter. In the wintertime, I leave the hubs engaged pretty much all winter, and shift in and out of 4wd on the transfer case. I'm only in 4wd when I feel there's a distinct benefit to using it. Parts DO wear more when you put more load on them, and it's enough of a PITA to change front U joints and ball joints I don't want to do it more than I need to, beside the cost of them!

When I need to make sharp turns, unless it's so slippery I can't do it in 2wd, I always disengage it.

My rule of thumb is "If you can feel the 4wd doesn't like it, you shouldn't be using it", and you really feel it when you try turning sharp even on gravel.

We have 1 very old 4wd tractor that we pretty much never use except for corral cleaning and subsoiling

 

[Brute 23]

Ya 4HI vs 4LOW has no effect on the 4wd. It's like running in 1st gear vs 5th gear. All the clutches are built in to the transfer case and differential.

Locking the hubs does not mean the axle is locked solid.

4LOW is great. When in real slick stuff like around feeding areas you can put in in 4LOW and roll right through it never spinning a tire.

I usually run in 4 High when it's wet so I don't spin. You can go down roads in 4wd and never spin a tire where a 2wd would be cutting ruts and making a mess.

 

[melking]

All that being said, I have a 2002 Dodge 1500 with 150,000 miles of which 50,000 are in 4WD. My two wheel drive stopped working at around 100,000???

 

[rockkkkkher]

Trying to find out info, though. ON MY 99-03 FORD F250 SD 4x4, MANUAL SAYS TO PUT TRANS IN NEUTRAL THEN SHIFT TRANSFER CASE TO 4L or 4H. QUEST> IS IT SAYS NOTHING ABOUT THEN SHIFTING TRANS INTO REVERSE. IF IM SUPPOSED TO KEEP TRANS IN NEUTRAL HOW CAN I GO IN REVERSE ? GET WHAT IM SAYING ? ALSO WONDER IF TRASFER CASE WAS IN 4L or $H AND I ACCIDENTALLY SHIFTED TO D-DRIVE on TRANSMISSION/column WHAT WOULD HAPPEN. Nobody has answered this in 5 years of asking.