Thread: D4 Traction Control System and Indications

Originally Posted by Celtoid

Essentially, I'm asking how the TC works and how does it tie in with the lockers?

Kev,

All landys are permanent 4WD, incl the D4. The only 2WD landy is the new base model Freeloader.

The D4 has a center diff lock and a rear diff lock, and 4 wheel TC. Basically the first thing that the system does in off-road mode is to lock the centre diff, then if one of the rear wheels is spinning, it locks the rear diff.

Beyond that it then engages TC selectively on the front wheels. At least this is how I understand it works.

If the D3/D4 does not have a rear e-diff, then when the rear wheels start slipping the 4-wheel TC kicks in selectively on all wheels.

Originally Posted by Celtoid

Anyway, on my 4WD touch-screen, there is a representation of the D4's drive train. There are two green lock icons, one on each differential. I believe the back icon represents an e-diff, if fitted.

Kev,

The back diff icon will only go red and lock if your bus has the optional e-diff fitted at the rear.

Mine doesn't, and I stressed about this - until I went on a training day with some experienced LR people. Then I discovered that with sensitive driving the TC will handle just about any situation - it very quickly works out which wheels are wanting to spin and which have traction. Knowing which settings to use seems to be pretty important - I was pretty clueless till I did that training outing. Now I just have to remember!

Funny how you don't look at things very clearly sometimes...

It's been hosing down in Brissy over the last few days and I took the truck for a play in the mud today. Because I'd written this thread, I looked really closely at the touch screen......

Yeah, it's showing a centre diff-locker. The top of the screen has the transmission selection icon on it.

So from what you guys have written, it will always find traction (in theory), as it will sense slippage on the other wheels and apply power to the ones that aren't?!

I guess that 'thinking' time explains why it looked like it had spun all 4 wheels in the mud today and the sand on Fraser Island......spin -think - adjust, etc?!

Thanks guys.

Regards,

Kev.

Originally Posted by Naks

Kev,

All landys are permanent 4WD, incl the D4. The only 2WD landy is the new base model Freeloader.

The D4 has a center diff lock and a rear diff lock, and 4 wheel TC. Basically the first thing that the system does in off-road mode is to lock the centre diff, then if one of the rear wheels is spinning, it locks the rear diff.

Beyond that it then engages TC selectively on the front wheels. At least this is how I understand it works.

If the D3/D4 does not have a rear e-diff, then when the rear wheels start slipping the 4-wheel TC kicks in selectively on all wheels.

Hi Naks,

It was a long time ago....but was I mistaken in what I saw with the 110? I'm certain it was two wheels not turning and the ones in the mud were....and then in unison after locking the centre?

I have killed a few brain cells since then.....

Cheers.

the e-diff is one trick unit, it can be sliped thru to locked at 100%lock, so its got 0-100% lock abilatly, that with tc is very good, seen it work and yer,, very nice,


tc the easy way,
1,wheel lifts
2 wheel spins
3 computer in the power of magic senise spin
4 computer tells brake on that wheel to slow it down,
5 drive is transferd to the other wheel on that axle,
6 other wheel terns,
7 you move ford in a ture amazment

Originally Posted by Celtoid

Hi Naks,

It was a long time ago....but was I mistaken in what I saw with the 110? I'm certain it was two wheels not turning and the ones in the mud were....and then in unison after locking the centre?

I have killed a few brain cells since then.....

Cheers.

Even a 'permanent 4WD' system will spin wheels as you've described, as the front and rear diffs shunt torque to the wheels with the least grip. Only if you have diff lockers or a _very_ good TC system (as in the D3/D4 ) will you spin all 4 wheels.

A '4WD on demand' system, if in 2WD mode, would only spin one wheel (usually on the rear axle), with no drive going to the other axle at all. Same as a std 2WD.

Cheers,

(clear as mud) Gordon

Originally Posted by gghaggis

Even a 'permanent 4WD' system will spin wheels as you've described, as the front and rear diffs shunt torque to the wheels with the least grip. Only if you have diff lockers or a _very_ good TC system (as in the D3/D4 ) will you spin all 4 wheels.

A '4WD on demand' system, if in 2WD mode, would only spin one wheel (usually on the rear axle), with no drive going to the other axle at all. Same as a std 2WD.

Cheers,

(clear as mud) Gordon

LOL...Thanks.

I guess the fact that industry has used the term 4WD for a system that can actually drive any of the four wheels, even if it's going to be the ones with no traction, is just a little confusing....hahaha

I remember back at Abingdon in the UK, many years ago. A Discovery 2 driver was showing off the traction control. He tried to climb a hill far too slowly (using the TC) but all he ended up doing was sitting there with all 4 wheels spinning at the same speed. I assume the TC would not kick in as it assumed since all 4 wheels are at the same speed the no wheel was slipping.

Ivan