Diff locks and tyre sizes on a TD 100 series

Though the Landcruiser is fulltime 4wd which I would have thought meant that one of the front wheels might be working all the time as well.2001 Landcruiser 100S Turbo Diesel
"We do not stop playing because we grow old; we grow old because we stop playing"

Andrew and Jen,

With a fulltime 4wd (centre diff unlocked) if you lift one wheel, all the power goes to that wheel (Trucksters 1-wheel drive).

If you engage the centre diff, then power goes 50% to front and 50% to rear, so if you lift one wheel, then the other axle still powers you forward.

If you lift one wheel from each axle, then you're going nowhere, unless you have diff locks, or a LSD that does a lot more than the standard Tojo LSD.

Phil G
Thinking about it logically, with all the diffs open, I guess that as you say, if one wheel spins, all the others lose power. Hadn't thought about it logically before. I remember seeing a car at the snow and the guy had put a chain on one front wheel and another on a rear wheel. The chainless rear wheel just spun uselessly when he was going up an icy hill.
How come in my Landcruiser I didn't use chains as they said I didn't need them, but my rear or even front wheel didn't spin uselessly the same. You would think that if all your diffs were open that you would only have to lose traction on one of the four wheels and you would be stuffed. I never engaged my centre or cross difflocks.
Andrew2001 Landcruiser 100S Turbo Diesel
"We do not stop playing because we grow old; we grow old because we stop playing"

Phil G

Keeping 4 wheels on the ground will give drive to front and rear even when the centre diff is not engeged. Having drive in the snow could be because the tyres, weight of cruiser and the rate of acceleration.

The centre diff allows the front and rear drive shafts to spin at different speeds eg. when going around a corner, just as the front or rear diff allows the inside and outside tyres on the same axel to spin at different speeds. Lock the centre diff and both front and rear drive shafts must spin at the same speed.

Wayne

Andrew, Wayne,

If you wonder about the LSD on your Landcruiser, then jack up one rear wheel on an axle stand, centre diff unlocked and attempt to drive it off. Chances are that it will do nothing. With a "good" LSD, it will only attempt to drive off with the brakes partly applied. This "loads" the LSD and it springs into its very limited action. Alternatively, some might say that you are simply using "poor man's traction control".

All 3 diffs on a fulltime 4wd are essentially open diffs - front and centre all the time, rear LSD most of the time. If you attempt all your 4wding without the centre diff locked, you are losing drive whenever traction is lost on any one of the 4 wheels.

With these vehicles, you MUST engage the centre diff whenever loss of traction is possible. Sure you'll still get through, but you'll chew up the track a bit more than you should and you'll put high loads on the drivetrain. (Ever wondered about the high number of diff breakages in full-time 4wds?)

Transmission wind up is not a problem once you are off the bitumen.

Cheers
Phil

Could not have said it any better Phil. Another way to check if your diffs are open or have some type of mechinical traction control.

1.Jack up axel front or rear does not matter which one, with both wheels off the ground.

2.Turn one wheel by hand, if the other wheel turns in the same direction, you have some form of traction control. If the wheel does not turn or turns in the opposite direction, open diff.

Wayne

Right decision Mike,

I lived with front and rear ARB dif locks for 6 years and they are wonderful.

When the bucks arrive in my bnak they are going in on the new car.

Duncs