Turning whilst in 4H

Hi All,

Had a problem this morning whilst trying to turn whilst my D40 ST was in 4H. I was travelling at about 5km/h truning at about 3/4 loc. Felt as though my front diff locked up. Is it normal to experince this or is there a fault in the system?

Cheers

There's no limited slip between the front and rear axles. On any solid surface, engaging 4WD of any type (4L or 4H) will just end up straining the transfer chain, differentials and inducing excessive wear on the tyres. Speed is not a factor. The tighter the turn, the worse the effect.

Basically you're binding up the wheels. In a tight right turn, the front left wheel is inscribing a circle much larger in diameter than the right rear wheel, yet both are connected via the transfer case.

If you're on a solid surface with decent traction, disengage the 4WD and you won't have any problems. General rule of thumb: never, ever engage it on tar. Other surfaces - engage as needed.

The D40 has no centre differential - this means that when attempting to turn a tight radius corner, the front of the vehicle will always feel like it is pushing wide. That is just part of the way a part time 4wd with no centre diff behaves.

Thanks Old Tony and antz oz, your info was much apprecaited.

Do that to often and you will kill the transfer case.

Id hate to see the price of a new transfer for a D40, everything else is more expensive then D22 parts.

Dave.

Dave said:

Do that to often and you will kill the transfer case.

Id hate to see the price of a new transfer for a D40, everything else is more expensive then D22 parts.

Dave.

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Out of interest.....do what too often? No harm in doing tight turns when in 4wd.

Well I was assuming he was on tar in 4wd. That will kill the transfer.

On gravel yeah it wont hurt.

Dave.

Dave said:

Well I was assuming he was on tar in 4wd. That will kill the transfer.

On gravel yeah it wont hurt.

Dave.

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Fair enough, I wasn't assuming anything - I didn't see anything in the original post to indicate what kind of surface the user was on - so didn't take anything from it.

On loose surface, my D40 "pushes" when turning tightly in 4wd (when travelling slowly), hence the reply I gave originally.

Na its cool, its best to give a few answers as not everyone knows not to use 4wd on tar if you have no center diff.

Dave.

Mine has done the same thing,
I had absolutely no Fu#*king idea what was happening,
I was turning in to a caravan park driveway towing the boat and it locked up on me and then i couldn't get it back in to gear.
I wasn't aware the you shouldn't drive in 4w4 on solid ground, I do know i suppose.

its all in the manual...

I was reversing my boat in low range on grass the other day and it bound up, mustn't have been soft enough to let the wheels slip.

the other night i picked up my rideon mower up in the adelaide hills. all up i was towing over 2 tonne easy. it was pissing down outside and the road back to town was realy windy and very narrow so i put it into 4h. as soon as i made it back to the built up areas i went back to 2h. did i make a huge mistake? ... i had no idea there was a problem?

4H or 4L are really only intended to be used when traction is questionable for continued movement. Rain-soaked tar is still tar and doesn't really need 4WD to negotiate.

You would have been straining the chain in the transfer case - these are big heavy chains, but the car's also big and heavy and unless a wheel can slip on the surface to release the tension built up by one wheel trying to go around a larger circle than another, the chain is the bit that gives way.

It's not something I'd do too often.

ta tony, i hope i havent screwed it. never knew there could be an issue. how do cars like subarus that are constant 4wd get away with it ... do they have a centre diff?

You nailed it. There's a LSD between the axles as well as in the middle of each axle. It's the only way you can have all 4 wheels driven at once on a solid surface without causing damage to the drive train.

There's a price for that (apart from the cost). All-wheel-drive vehicles aren't quite as capable as ours. Ours are improved with lockers - devices that lock our diffs so that there is no slip at all - in some situations, you need power delivered even when a wheel has left the ground.

(I over-explained that for the benefit of the readers that didn't know how they worked).

Edit: added the bold text.

I prefer a part time 4wd system as it is less wear and tear on the driveline.

Thats a downside the D40 has aswell as they have no manual locking hubs compared to the D22. In general driving the rear diff is only getting wear and tear.

Dave.

Do a 4wd driving course such as one from my good friend Ricky Esser from Follow Me 4WD Pty. Ltd.. He is more than happy to recommend equivalent training operators in other States.

[disclaimer: a blatant free plug for Ricky ]

Seriously for novices you will learn heaps of stuff you never knew!