4llc explanation

[kellaig]

Hi there,

i have a 2003 NM Pajero that I got bogged today. The front whhels were not bogged but the rear ones were. In low range i thought that all wheels were locked and turned the same. Today the rear wheels spun madly, whereas the front ones either didn't turn at all or slower than the rears.

Once out of the bog, and towing the boat trailer out via a strap all wheels spun together. Is this normal when all wheels aren't bogged and get grip.

Can someone please explain this???

regards

Kellaig

[nj swb]

Hi there,

i have a 2003 NM Pajero that I got bogged today. The front whhels were not bogged but the rear ones were. In low range i thought that all wheels were locked and turned the same. Today the rear wheels spun madly, whereas the front ones either didn't turn at all or slower than the rears.

Once out of the bog, and towing the boat trailer out via a strap all wheels spun together. Is this normal when all wheels aren't bogged and get grip.

Can someone please explain this???

regards

Kellaig

In 4LLc your centre differential is supposed to be locked, so you should have at least one wheel turning at the front, and one at the rear. You still have open diffs front and rear, so one front and one rear spinning will immobilise the vehicle.

From your description, I suspect your transfer didn't lock the centre diff properly when you were bogged - but it's difficult to be certain.

[pjchris]

...You still have open diffs front and rear, so one front and one rear spinning will immobilise the vehicle....

Didn't all NM's in Australia come with the LSD at the rear?

Peter

[jol]

Didn't all NM's in Australia come with the LSD at the rear?

Yes I think so. Still one front and one rear wheel without traction, they will both spin, as it is a torsen LSD, so you need some traction for it to work.

[pjchris]

Yes I think so. Still one front and one rear wheel without traction, they will both spin, as it is a torsen LSD, so you need some traction for it to work.

True, but pulling the handbrake on a couple of notches is sufficient to do that....

Peter

[kellaig]

Thanks for the info,

that's exactly what was happening. i had diagonal wheels free spinning (one on the front and the other side at the back)without traction and the others weren't turning.

Is this normal and what would putting the handbrake on do??, allow both wheels on the back to turn.

I am a novice?

regards

Kellaig

[pjchris]

Putting the handbrake on, or left foot braking (Lightly) provides some drag on the wheels that are spinning which will transfer some of the torque to the wheels that are not spinning.

With the rear having a Torson diff as long as the spinning wheel encounters some traction or resistance it will tend to lock up and transfer drive to the other wheel.

This can be enough to get out of some situations as then you have to have three out of four wheels with no grip to get stuck.

Peter

[Monterorider]

Pulling handbrake MIGHT produce enough torque on rear wheel without traction to transfer enough torque to opposite wheel to either overcame resistance force preventing vehicle from moving or start it spinning as well. If there is not enough torque transfered the wheel without traction will continue happily spinning. Diff will start to warm up. There is always some torque available on opposite wheel since Gen 3 is equipped with Hybrid LSD which is indeed hybrid of Torsen LSD and Viscous coupling. As one wheel spins viscous coupling warms up and provides some preload to torsen unit thus some torque to opposite wheel is transfered but usually not enough to overcome serious obstacle. Like crossing deep ditch for example. Handbrake might add that little extra needed or might not.

[psproule]

Having use it to great effect on our NM I can attest that the handbrake trick does work well with the Torsen LSD.