Driving long distances in H4

Submitted: Monday, Feb 13, 2012 at 08:32
ThreadID: 91832 Views:4312 Replies:16 FollowUps:12
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Hi all,

Just wondering what the thoughts were on driving long stretches of dirt roads in H4 instead of H2. In some places the roads are a bit loose, so was aiming to lift the safety level of the drive. I expect not to be doing much over 80km/h.

Are there negative effects on the vehicle doing so?

It's an 'old fashioned' manual hub locking HiLux 4x4.

Thanks.

Joshuah
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Reply By: Member - Tony V (NSW) - Monday, Feb 13, 2012 at 09:15

Monday, Feb 13, 2012 at 09:15
In my opinion and if you are not going over 80kmh, then it is sensible to utilise the 4WD ability that you paid for.

Putting traction through to both axles is better than just one.

Some will say fuel cost will rise and other will say wear and tear...

But most newer 4WD's do not have free wheeling hubs, so that theory seems depleted.

As I said, thats my opinion, I am sure that there will plenty of others... :)
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Follow Up By: Member - Frank P (NSW) - Monday, Feb 13, 2012 at 09:56

Monday, Feb 13, 2012 at 09:56
Tony,

I think that's because they either have automatic hubs which are free-wheeling when 4WD is not engaged, or the vehicle is All Wheel Drive when not in 4WD, á la Prado and I'm sure, others.

Frank
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Follow Up By: Member - Tony V (NSW) - Monday, Feb 13, 2012 at 13:06

Monday, Feb 13, 2012 at 13:06
Not quite Frank.

As I said, most newer 4WD's do not have free wheeling hubs.

HiLux, DMax- Colorado, Amarok, Pajero, Navara, Pathfinder, Jeep Wrangler and many more all have part time 4WD and the front hubs are fixed so they run all the time, not free wheeling or automatic.

The new troopy and Nissan Patrol do have free wheeling or auto hubs (Nissan).

The Land/Range Rovers, Landcruisers and Prados have constant 4WD.
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Follow Up By: Member - Frank P (NSW) - Monday, Feb 13, 2012 at 19:05

Monday, Feb 13, 2012 at 19:05
Thanks Tony,

Well, I did say Prado and others. It seems there aren't many "others" - but in my own defence there are some! :-)

The list you quote really surprises me. I would have thought that in this era of a relentless drive for fuel efficiency a parasitic load like that would be one of the first to be addressed in newer 4WDs.

Leaving aside transmission wind-up on hard roads, it would seem to take the worry out of the wear and tear issue if you choose to use 4HI on loose gravel roads - ie if the drivetrain is turning all the time, might as well use it (surface permitting).

Frank

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Reply By: MrBitchi (QLD) - Monday, Feb 13, 2012 at 09:20

Monday, Feb 13, 2012 at 09:20
On loose gravel you'll have no problems and the car will be more stable. Just make sure you go back to 2wd on the hard stuff. That includes hard, clean dirt surfaces, ie not covered with loose gravel. That's just as bad as tar for transmission windup.
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Reply By: Gossy - Monday, Feb 13, 2012 at 09:40

Monday, Feb 13, 2012 at 09:40
yep that's what it's made for so no long term issues.
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Reply By: Member - Royce- Monday, Feb 13, 2012 at 10:27

Monday, Feb 13, 2012 at 10:27
"long distances"..... that might be the important part of your question.

If you say drive 100ks of 'dirt road', you may end up travelling for a couple of ks on firm surfaces where diff wind up might be a problem. Generally though at around 80ks you shouldn't have a problem.

I tend to not have the hubs locked mostly because I then forget to unlock them!
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Reply By: The Bantam - Monday, Feb 13, 2012 at 10:43

Monday, Feb 13, 2012 at 10:43
It does not matter what speed you are doing, if you are on loose surfaces you should be in 4wd.

Many mine sites require 4wd to be engaged when you come thru the gate, the army and many institutional users of 4wds, require 4wd to be engaged on all "unmade surfaces"

The improvement in stability and steering control is considerable.

Where is makes a huge difference is on well made roads that see a lot of traffic...good roads ,fast roads..... as a result they have a good hard smooth pack but they have a loose top surface with lots of marbles along the edges and on the outsides of the corners.

when you meet another vehicle and have to take the outside line on a corner on such a road you will either wish you were in 4wd or bless the fact that you are.


As far as a dirt surface with sufficient traction to cause transmission wind up...that would be a very rare thing indeed..it would have to be a very hard packed road with a lot or rock in the top course and devoid of all loose material.

as far as any top speed.
the faster you are going the more you need to be in 4wd...there are many competitive 4wds that do well over 100Kph for days at a time in 4wd.

There is no good reason, to not engage 4wd where it is appropriate.

As a matter of safety and comfort...use 4wd in any situation it can give you an advantage......that is what you paid for.

what you should do is find out the habits and requirements of your transfer case and practice the shift from H4 to H2 and back again..........for those irritating short sections of bitumen you will find in the middle of nowhere.

cheers
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Reply By: Joshuah - Monday, Feb 13, 2012 at 11:56

Monday, Feb 13, 2012 at 11:56
That's great info.

I asked this question to someone who repairs them, and he looked at me oddly when asked. "Why waste the fuel?", was the reply.

I use H4 when coming out of rough spots on the short dirt stretches and notice the huge improvement in handling on corrugations. I naturally would prefer this handling all the time, but wasn't too sure what 5-600km would be like for the car, in one day.

It seems it'll handle it from the above responses. I may take an extra Jerry of diesel, though...

Joshuah.

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Follow Up By: Member - Scott M (NSW) - Monday, Feb 13, 2012 at 12:22

Monday, Feb 13, 2012 at 12:22
Josh, In my humble opinion this fuel issue is a load of bull-dust.

The difference on loose surfaces between 2wd & 4wd in term of usage is negligible at best, I would argue the better handling negates any notional fuel saving. In fact my Diesel 40 series gets better fuel figures on loose surfaces than it does on hard-top. There's also the safety factor of better handling in 4wd for certain vehicles.

My rule of thumb, keeping in mind I have no centre diff, is when I know I'm starting on a long stretch of gravel/dirt is to lock in the front hubs, and selectively engage H2 / H4 when appropriate, but if I'm going to do more than say 80-90 km/h, then I will engage H2 to avoid transmission windup, the theory being that if you can travel at these speeds then 4wd isn't probably an issues anyway. Anything less than this the I stay in H4.

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Follow Up By: garrycol - Monday, Feb 13, 2012 at 12:35

Monday, Feb 13, 2012 at 12:35
Both my 4wds are contant 4wd (one over 35yo the other new). In both I engage the centre diff lock as soon as I am off the bitumin. It reduces wear and shock on the cdl and substantially improves driving stability and basically makes the vehicle the same as and older part time 4wd in 4wd.

I would lock it up - the wear an fuel consumption issue is a furfy. Oh I often forget to take the cdl out of lock when coming back onto good roads - so make sure you remember.

Garry
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Reply By: Member - Oldbaz. NSW. - Monday, Feb 13, 2012 at 12:57

Monday, Feb 13, 2012 at 12:57
Interesting question, and while I have no argument over anything said (except fuel & tyres) I find no motivation to lock my hubs in on unsealed roads. I believe it uses more fuel..my hilux sprayrig uses 20% more with the hubs in while spraying at 15KPH
2nd gear low range, than without & turning circle increases immensely. Avoiding
rocks etc ..eg steering..is much easier & accurate in 2wd. Perhaps that doesnt transfer
to onroad driving, but I cant see why not.
Front wheel drive increases tyre wear..fwd tyres wear out at a higher rate than than
rwd..in my experience anyway. I suspect such wear is increased by driving constantly
with the hubs in.
Does it really matter?..Probably not, but I dont see the perceived safety/handling
advantages being greater than the downside.
Whenever this topic comes up among my considerable number of farming 4wd
driving colleagues, the answer is ..no...burns fuel & stuffs tyres....
but what would a heap of old cockies know anyway?..:)))))).......oldbaz.
your hubs....your choice.
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Follow Up By: The Explorer - Monday, Feb 13, 2012 at 14:57

Monday, Feb 13, 2012 at 14:57
Hi

Driving at 15kph and driving at 80kph are different. You are not exactly going to go a bit sideways at 15kph (well not normally:) WRC rally drivers would look at you a bit strange if you told them the advantage of AWD/4WD was "perceived". AWD/4WD provides a real benefit. Most people are not going to drive around like a rally driver but there is no denying vehicles handle better and are safer if driven in AWD/4WD mode on gravel roads at normal speed.

Up to the individual to sus out if it is necessary for their circumstance and if suggested possible downsides (e.g. increased tyre wear, fuel consumption, mechanical wear) actually amount to anything worth taking into consideration. I personally doubt they do.

Plan B is of course to maybe go a bit slower and then you will save on everything :)

Cheers
Greg
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Follow Up By: Member - Oldbaz. NSW. - Monday, Feb 13, 2012 at 16:00

Monday, Feb 13, 2012 at 16:00
G'day Greg, you attest that driving at 15kph & 80kph are different & I'll go with that.
My " perceived safety & handling advantages" refer to driving on unsealed roads at
around 80kph, with hubs in or out. I dont see that WRC drivers are relevant.
Your suggestion that I'm not likely to go sideways at 15kph is amusing but I'll let it pass as well, as I assume you are talking "onroad". Do you expect to go a bit sideways
at 80kph on a dry unsealed surface in 2wd, or do you think being in 4wd will cure it
if you do ?. Anyway, you are of the opinion that vehicles handle better & are safer
in 4wd on gravel roads at normal speed, and I dont agree. I prefer Plan B, in 2wd.
The best part is that we can both use our experience to make our own decision, &
discuss it amicably on EO.Cheers.......oldbaz
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Follow Up By: Member - Scott M (NSW) - Monday, Feb 13, 2012 at 17:15

Monday, Feb 13, 2012 at 17:15
"Anyway, you are of the opinion that vehicles handle better & are safer
in 4wd on gravel roads at normal speed, and I dont agree."

While I agree each to his own, you certainly would re-think if you were driving a 40 series without power steering...... :-)
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Follow Up By: The Explorer - Monday, Feb 13, 2012 at 19:26

Monday, Feb 13, 2012 at 19:26
Hi again.

Sorry, my point about WRC drivers is that they all use AWD vehicles these days - there is a reason. Have a think about it. They arent doing it because I told them to and I doubt if you gave them a ring and told them the "truth" they would all swap back to 2WD.

I have no idea where you drive at 15kph so I suppose my statement was a bit generalised..but you know what I meant...

...and I understand your point of view.

Probably no big difference in a lot of circumstances and therefore maybe saying that being in 4WD is better is being a little bit pedantic.. but so be it.

4WD at a slower speed on a gravel road is even safer than 2WD at slow speed - try it :) ...it certainly cant be worse.

Cheers
Greg
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Follow Up By: Crackles - Monday, Feb 13, 2012 at 21:19

Monday, Feb 13, 2012 at 21:19
Baz I too don't see how your comparison of a spray rig doing 15 KPH in a padock doing hundreds of full lock turns is any where similar to the benifits you'd get with a high speed vehicle on loose gravel. Obviously in your case you'd get heaps of axle wind up (except in wet conditions) so would be pointless engaging 4x4, in fact the wear & tear particually on the CV's would be horrendous.
Cheers Craig.........
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Reply By: Member - Joe n Mel n kids (FNQ - Monday, Feb 13, 2012 at 13:45

Monday, Feb 13, 2012 at 13:45
Short answer ........ NO .............
If it an "older" 4wd with free wheeling hubs it drives like crud with them in and uses more fuel and yes i have trialed it long distances out and in and it is far better to drive it with hubs OUT and OUT of 4wd, gearbox will last longer as will diffs and transfer case, it will run cooler in the gearbox and really if you lose traction to the point when it has problems moving forward, then and ONLY then put it in 4wd ....... yep new cars have constant 4wd and are designed for that, old ones aint .... and i know for a fact in the Hilux's and 75 cruisers they are harder to control if the 4wd is in, it tends dart and jump around, more so on loose surface's .........
The MOST critical factor that needs altering according to conditions is tyre pressures ..........
Cheers
Joe
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Follow Up By: Member - Oldbaz. NSW. - Monday, Feb 13, 2012 at 14:11

Monday, Feb 13, 2012 at 14:11
Aaaaah ! Joe....You're a little champion..:)))). Fancy agreeing with me . We must
be careful now....the "off the tar..into 4wd" hordes are starting to outnumber us.
The decision about 4wd or not has been removed from most of them anyway. Only
the likes of you & I can really decide if we want 4wd or not...& you too Joshua.....
cheers......oldbaz.
PS...makes you wonder how me,you, & the thousands of us that drive unsealed roads
in 2wd cars every day ever survive at all, doesnt it ?.
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Follow Up By: Michael ( Moss Vale NSW) - Monday, Feb 13, 2012 at 20:42

Monday, Feb 13, 2012 at 20:42
Hey Joe! It might be all over the road in a Toyoya (your words) ;)) LOL! but in a Patrol, its Bliss!! No different. I dont go along with the wearing out the diffs, i assume you mean the front diff! My Patrol has 330,000ks on the clock and the front diff has only done a few thousand, it will never wear out!! I think its better to run the front diff and the cv's every now and then! Anyway, everyone has a view and can have a say, thats the beauty of the forum.. Cheers Michael



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Reply By: brianc - Monday, Feb 13, 2012 at 15:55

Monday, Feb 13, 2012 at 15:55
I'm for it. If I have any concerns with wind up, I occassionaly flick it out of H4 and then back in on the run. There hasn't ever been a time when it was stiff to get out, indicating a bit of wind up. As for handling (particularly older stuff with no ABS etc) just try doing an emergency stop in H4 and H2 and compare the difference. I do it for the decreased stopping distance alone.
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Reply By: Outbacktourer - Monday, Feb 13, 2012 at 17:04

Monday, Feb 13, 2012 at 17:04
When I had my Patrol ('02 3.0Di) I would engage 4H as soon as I hit the dirt. Nocticeably more stable, particularly with a load on, less chipping on the rears and no noticeable difference in fuel economy. Never bothered with short causeways and so forth but longer stretches of blacktop I shifted out on the fly. Probably covered 70,000K this way. Sure the T'fer case fluid looked like it was 'used' come change time but that's what it's for eh! Did it with the Jack I had before that. The Cruiser I had was born that way and D4 I have now does it for me + a lot of other stuff.

IMHO if you are not doing it you are leaving grip on the table.

OBT
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Reply By: Member - Mfewster(SA) - Monday, Feb 13, 2012 at 17:21

Monday, Feb 13, 2012 at 17:21
I completely agree with Tony and Mr. Bitchi. if you note that you have stretches of hard paked stuff, jus ease. the left wheels onto the shoulder avery so often(at suitable speeds of course)
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Reply By: Michael ( Moss Vale NSW) - Monday, Feb 13, 2012 at 17:32

Monday, Feb 13, 2012 at 17:32
HMMMM !! Its a bit long winded to read all but I have on many occasions, on corrugated and rough dirt roads, run in 4H.. I reckons it smoothes the ride and gives more control to the driver.. The fuel thing is debatable, I think it does not matter that much, if it uses extra fuel, it cant be much extra and when you are away, you expect to use extra fuel if you encounter hard going tracks.. My thoughts only!!! Michael









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Reply By: Joshuah - Monday, Feb 13, 2012 at 18:43

Monday, Feb 13, 2012 at 18:43
Righto, but I'll give it a go.

Although the manual states that H4 is for 'wet, icy or snow-covered roads', I'll assume dirt and corrugations fits in that part too.

Good point about the heat of the transfer case and front diff. More regular oil changes would help there. But safety if key, so I'll use it when the going gets loose.

It's been bloody helpful, all these replies. Thanks!
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Reply By: Crackles - Monday, Feb 13, 2012 at 19:18

Monday, Feb 13, 2012 at 19:18
I engage 4x4 on most dirt roads if there's loose or slippery surfaces. (The distance & speed is pretty much irrelivant) Overall using 4x4 gives you greater control, improved braking & on some surfaces minimises the formation corrugations.
Negatives: I wouldn't do it if your tyres wear or size was different.
Fuel consumption on my "old fashioned' manual hub locking HiLux" increased by 1 to 2 MPG. (1/2 a litre per 100) Cheap piece of mind & you certainly wont need another Jerry-can Josh ;-)
Cheers Craig.............
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Reply By: Rockape - Monday, Feb 13, 2012 at 20:49

Monday, Feb 13, 2012 at 20:49
Joshuah,
I have done what you are talking about many times with a difference.

I will lock my hubs in and run high 2wd and if the road I believe is dodgy and I need high 4 I just pull the lever. I don't care what speed I am doing when this occurs as everything is in harmony front and rear drives are travelling at the same revs.

I also agree with Joe and Mel about the handling of an old style part time 4wd like his and mine. They do tend to dart about.

You will use more fuel and you will have more wear.

I know you are talking about a gravel road and not a wheel rolled clay road so you won't suffer from wind up at all.

As for transfer and front axle wear you will get that but in the big picture I would not worry about it. We run locked low range 4wd and some of these vehicles do 100,000k in this manner. They also run on bitumen for around 2k a day with 90 degree turns and all they destroy is CV's which are partly destroyed by much turning and full torque all day.


I find mostly I just stay in 2wd and travel at a speed that suits the road or track.

Have a good one,
RA.

PS. once drove 100k accidentally up a twisting highway with the cross locks engaged on a prime mover and loaded trailer. Didn't tell the boss and that truck went on to clock up well over 1,000,000 k on it's original rear end.



AnswerID: 477686

Reply By: Wayne David - Tuesday, Feb 14, 2012 at 12:31

Tuesday, Feb 14, 2012 at 12:31
Loads of good advice on here.

Just as an extra.....and if you are interested - Pop onto the Bridgestone Tyres website where there's a really good video demonstating the advantages of 4x4 over 2x4 on gravel roads in the Flinders Ranges.

It's for the D694's but equally applicable to any tyre.

Even on my relatively quiet dirt road I now always switch to 4x4........just in case.

All the best - Wayne
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