Use of H, HL and LL?

[kzj90nz]

Hi guys,

I've just bought a KZJ90 to use for a construction project in an alpine area.

I could do with some clarification regarding the use of H / HL and LL.

Is the transfer case meant to be easy to shift through when the car is running and in park? Mine is really reluctant to go through the different modes - is there a release mechanism that I've overlooked?

Does everyone generally use HL when it's raining? Anything to be weary of when that mode is selected - ie handling / braking / fuel usage?

How does everyone select HL? Can you do it as you're driving?

If you're towing do you use H or HL and hit the PWR button?

I know that you need to be stopped and in park/neutral to select LL.

Thanks a lot!

 

[Shayne]

H = high gearing for normal driving on hard ground rain or shine .
HL = high gearing locked centre diff for high speed with poor traction , on snow or mud or gravel maybe .
LL = low gearing and locked centre diff for extreme off road .

Its a full time 4x4 so all of the above applies with or without a trailer .

 

[kzj90nz]

Good stuff - I'll print that out and put the instructions in the truck in case I forget, or if friends/family use it

 

[Bob]

The transfer lever won't be as easy to shift as a normal manual box, or your auto. It will be a touch more clunky, but shouldn't need a huge force either. Just be careful about using HL on dry smooth tarmac.. the transmission won't like it for extended use. It's for loose surfaces as Shayne says

 

[uHu]

as above, + change to LL only when standing still and gearstick i Neutral. When changing from LL to High range, you can roll at walking speed, as long as gearstick is in Neutral.

 

[MicheleCasta]

H = high gearing for normal driving on hard ground rain or shine .
HL = high gearing locked centre diff for high speed with poor traction , on snow or mud or gravel maybe .
LL = low gearing and locked centre diff for extreme off road .

Its a full time 4x4 so all of the above applies with or without a trailer .

I have a 1999 Land Cruiser Prado KZJ90L. There is a separate dash knob for locking the REAR differential in ALL gears. Both HL and LL automatically lock the CENTER differential. The CENTER differential CANNOT be locked on H to prevent you from wrecking the transmission. This model is permanent 4x4. Some mechanics are not familiar with Land Cruisers because is not a very popular car and not often needs a mechanic ;-)


H = high gearing for normal driving on hard ground rain or shine.
HL = high gearing (not as high as H) with automatically LOCKED center differential for “high speed” with poor traction, on snow or mud or gravel maybe. The car in this will feel restrained almost as if it had the emergency break partially on compared to H. (The “high speed” terminology is not quite correct.)
LL = low gearing automatically LOCKED center differential for extreme off road.

This Land Cruiser is a full time 4x4 and I’ve done trails steep to a level that only a quad could do simply on H. So these other gearings are really for EXTREME, EXTREME situations and going straight. The differential lock can cause extreme harm to the transmission if not used for what is intended.

 

[MicheleCasta]

H = high gearing for normal driving on hard ground rain or shine .
HL = high gearing locked centre diff for high speed with poor traction , on snow or mud or gravel maybe .
LL = low gearing and locked centre diff for extreme off road .

Its a full time 4x4 so all of the above applies with or without a trailer .

 

[Shayne]

L on the shift nob is locked . The dash switch is a rear diff lock usually only seen in UK spec trucks , this will only engage when LL is also engaged .

It can be switched on the move at slow speeds when your almost certain you will get stuck but in reality its a magic button that makes a big difference when your already stuck .

Diff locks are detrimental to performance , they try to force the vehicle forwards in a straight line and the 90 series is very capable off road in standard H mode because its a permanent 4x4 . However diff locks are a godsend when you lose traction because the 4x4 system sends power to the wheel with the least resistance which is inevitably the one that's spinning in mud not letting you move . Lock everything and only one wheel needs to find grip to drag you out of trouble .

Engage them now and then in a straight line at very slow speed just for a few yards to keep them freed up and working . Other than that they should only enter your mind when you think its not possible to drive this through/over that .

Familiarity comes from playing silly buggers off road when your sort of trying to get stuck for fun , though the next fella will say its all about testing your vehicles capabilities .

 

[BobMurphy]

When you are in 'LL' and turn the 'diff lock' switch on you should see a Red four-wheel symbol on the dash - just like that Amber one but with the cross in the centre of the rear axle. Are you getting that??
If not, I'm afraid your rear diff locker needs looking at (he says, diplomatically).
For info' - the Continental versions of the '90' (known as Prados) have 'limited-slip rear diffs' instead of the electric diff locker. They also have inter-coolers, which the UK versions don't.
Welcome to the educational world of the 90-series !
Bob.

 

[RichC4]

From my manual, some info on speeds you can switch at. For auto gearboxes, use neutral instead of the clutch.