Hi
always thought mud equals need for 4x4 for traction, however just gone over mountains in Romania despite being gravel roads no traction problems. How ever did wonder if using 4x4 capabilities would share out load on diffs and improve pulling capabilities up steep climbs due to pulling as well as pushing. Vehicle is iveco 4x4 40.10w approx 4 ton. any advice would be welcome
thanks mark

Depends on a number of things really - if you have permanent 4x4, running through diffs or viscous couplings then that tends to be ok in most circumstances, and you only need to start engaging difflocks to lock axles together or lock wheels on an axle when there is a serious chance of traction being lost.

I crossed th Ubari sand sea in Libya without using difflock once - a fact I only realised when I got home and found the guys who overhauled my transfer box never attached the end of the difflock lever!

Sometimes using difflock can be a disadvantage - turning hard in sand can make the outside wheels dig in and sink, and there are also times if you need to use heavy throttle that you might want a wheel to be able to spin so you don't snap a drive shaft. A lot of the decisions on when to engage will be down to the individual vehicle, it's mechanical traits and the environment.

You don't always need locked 4x4 in mud or slippery surfaces as unless you are turning or the wheels are on different types of surface, they should get roughly the same level of drive to them anyway unless something happens that makes the diff change which axle/wheel gets the drive.

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With the iveco you need to be on a loose surface to use 4x4 as it it part time 4x4 with no centre differential so you risk transmission windup on hard services

i would probabily leave it in 4x2 but with the hubbs locked in so you can go to 4x4 if needed without getting out of vehicle on that sort of terrain

rich

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Rich

Iveco Turbo Daily 4x4 40-10
Ex Owner LR101 300Tdi Ambi 'Tiggurr'

Hi,
I agree with Rich. In my 60 I lock the hubs at the start of a pieste/track, but only engage 4x4 when needed and certainly not on any hard surface.
Its good practice to lock the hubs every couple of thousand miles anyway to stir up the oil in the front axle, even if you have on intention of engaging 4x4.

All the best
Sam

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having had permanent and switchable 4x4 system landies and a landcruiser, assuming a loose surface, whats the disadvantage to engaging fwd anyway? (unless you have free wheeling hubs the whole lot will still be turning, so fuel consumption would hardly be affected?) if you start loosing traction it may be too late for fwd to unstick you, and concentrating on whats infront of you rather than "wheres that bloody lever/switch" is a better plan?

despite my current transport being part time 4x4, the handbook states i should engage the front axle if encountering steep grades or towing regardless of surface in the lower gears

As long as the surface is loose, then no harm at all.
Unless anyone wants to correct me, i certainly wouldn't ever engage it 'regardless of the surface'. It wont do any harm as long as you are going straight ahead, but there's only so long you can do that for! In the bends the transmition will wind up if the wheel can't slip

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grizzly

does your current transport have a centre diff, in that case its fine to engage it anytime otherwise i would be wary of doing that on an iveco or series landrover as even at low speed on tarmac you can get windup

rich

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Rich

Iveco Turbo Daily 4x4 40-10
Ex Owner LR101 300Tdi Ambi 'Tiggurr'

The handbook actually says engage 4x4 for "four wheel drive heavy-duty traction operation", and with diff locks for "extreme downhill and uphill. Heavy-duty traction and winter operation on loose ground or for off road driving (agriculture and forestry)".

Then a warning saying don't lock diffs on firm ground due to extra tyre and engine wear and the risk of accidents. No warning saying don't engage 4x4 on firm ground!

The section on trailer operation says engage 4x4 with heavy trailer loads. Definitely above 20000kg

On the CJ7, Ser III lightweight, '93 LR 90, 07 'cruiser i've had i was fully aware that a locked 4x4 system is a no no on tarmac etc. I was interested to read the above in the handbook, so not surprised people are implying i'm talking !!

My wheels She's Arrived!


edit:- I had written engaging centre diff lock in the above, but i don't have one. If i did it must now be hiding behind the sofa. Sorry. Weird how "engage centre diff lock " and "engage 4 wheel drive" meant the same when i typed it. Should have engaged brain before anything else

ah so you have a centre diff.

i still wouldn't lock the centre diff on tarmac , you can get transmission windup, my 101 was permanent 4x4 with centre diff and you could get windup on that involving a reverse to get out of difflock

So the advice for 4x4 with big loads is probabily correct and use the diff locks only when needed

my front difflock is a push button only so you cannot even lock it on and is definatly for loose surface only as i think Luke, prev owner did serious damage to it once very quickly

Rich

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Rich

Iveco Turbo Daily 4x4 40-10
Ex Owner LR101 300Tdi Ambi 'Tiggurr'

see edit to my above post

Interesting..... so a mog is happy in 4x4 on firm ground clever engineering ?

or i'm just confused ? yep thats it

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Rich

Iveco Turbo Daily 4x4 40-10
Ex Owner LR101 300Tdi Ambi 'Tiggurr'

If the transmision is built to tow 20 tons, maybe a bit of wind up isn't the end of the world for it!!!

Happy travels
Sam

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I would think happy is the wrong word! I am assuming if it was towing 20tons you would need as much traction as possible, with none of the load on the driven rear wheels like an artic unit. With such a load thru the transmission, wheelspin in 2wd would not be healthy, so the lesser of two evils perhaps?

Similarly, extreme machines on skytv showed a unimog towing a train as they are all capable of doing suitably modified, tyres on tracks, guide wheels engaged, 4x4 engaged, no wheelspin wanted, can't remember about difflocks. Again from memory, if you opted for all four gearboxes, 1st is something like 400feet per hour!

Although this would create transmission wind up it is what the handbook says to do.

When we've been driving up some steep hills (1 in 3, 1 in 4) and our speed is gradually reduced from perhaps 40mph at the bottom, because there is an air operated gate from the top 4 gears to the bottom 4, changing from 5th (say 15mph) to 4th (12mph) takes too long, we've lost too much speed and a hill start is required, probably in 3rd. Initially that is all i did, but you can feel the flexing in the transmission as it takes up the load again. Having read the manual it says 4x4 for steep or high traction (and high torque) conditions, so having tried hillstarts with 4x4 engaged on tarmac its a much more pleasant experience! Mostly you can get up into 4th again, and the lull in power during gear changing is enough to drop out of 4x4. Or wait till you get to the top.

The occasional article in UK 4x4 mags on Police vehicles usually mentions the possibility of certainly Landy products, maybe others, towing fully laden artics out of harms way, low box 1st.

I was initially only trying to illustrate a variation to what i'd always thought as a golden rule- no locked centre (diff or clutch) on a high traction surface. Its not something I would normally do. Thats not to say you can't, and people do if a lot of torque will be put on the system.

that explains it, mine can't move out of /into 4x4 on the move to my knowledge in an iveco - thats what you get buying a unimog

Just shows the rules apply except when they don't

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Rich

Iveco Turbo Daily 4x4 40-10
Ex Owner LR101 300Tdi Ambi 'Tiggurr'

Ok got this totally wrong mixed up diff lock with free wheel hubs however diff lock info very usesfull.

1) So does 4x4 engagement help uphill

2) Does any body know how my diff lockers work on the iveco 40.10w manual does not seem to help.

Rear is obvious as its direct by cable front less obvious as it appear to go into a box with electrics. What does this box do?

Tried opening but screws are seized will try and tackle later!

Thanks mark
Jo and Mark Overland