Need Clarification on FZJ80 4x4 System (1 Viewer)

[ewillis]

I have a 1994 FZJ80 without the factory lockers.The LC is full time 4x4 (that much i know due to the nice label on the tailgate), but what happens when I put it in 4 hi or 4 low? Do the front diffs lock in high and then the rear diffs lock in lo?

 

[scottryana]

If you don't have factory lockers in the axles the only thing that locks is the center diff. It will lock when you go into low range. But since your axles are both open really you will only have "2 wheel" drive. 1 wheel in the front and 1 wheel in the back.

 

[ewillis]

What happens when I put it in 4 hi?

 

[scottryana]

It is always in 4 high.

While in 4 high your axles are open so each axle sends power to the tire with the least resistance, and your center diff send power to the axle with the least resistance it is possible to have 3 tires on pavement and 1 tire on ice and spin that tire and the rest of the tires will get little power.

http://auto.howstuffworks.com/differential3.htm

 

[DSRTRDR]

do you have a CDL switch ? was an option in '93s and '94s

all wiring harnesses have the plug that allows you to install the CDL switch even if it didn't come in the truck

 

[ewillis]

No CDL switch, but I have a traction control button. I get that it's always in four wheel drive, but the hi/low option confuses me. I'm used to a truck that has to be put into 4 hi or low to be in four wheel drive, the Land Cruiser is kinda different...I don't get it yet. I know that people with the factory lockers claim 3X locked...that would be front, rear, and center...so don't I have two of those options?

 

[half k cruiser]

I thought CDL switch was only an option in 91 and 92 ? I have a 94 and got the switch out of a 91.

 

[scottryana]

Ok in a normal truck you drive around in 2hi, and when you need 4 wheel drive you usually get out and lock in the hubs and then shift into 4hi. This is the condition that the 80 is always in. It is always in 4 wheel drive high range. High range just means that there is no gear reduction in the transfer case it is 1:1.

In a normal truck when you shift into 4LO all it does is change gears in a transfer case so you go 2-3 times slower than in high range. In the 80 you get the lower gears but you also get the locked center diff.

And yes you are missing 2 of the locker options, the front and the rear. To equal the factory lockers you can put in ARB's, rear mechanical lockers, etc.

 

[ewillis]

OK...thanks, that makes sense. The hi is just reduced gearing and the low is center locked 1 front and 1 rear and the other two are limited slip?

 

[scottryana]

OK...thanks, that makes sense. The hi is just reduced gearing and the low is center locked 1 front and 1 rear and the other two are limited slip?

Ummm no --

High range just means that there is no gear reduction in the transfer case it is 1:1.

when you shift into 4LO In the 80 you get the lower gears but you also get the locked center diff.

you are missing 2 of the locker options, the front and the rear. To equal the factory lockers you can put in ARB's, rear mechanical lockers, etc.

You do not have any limited slips and you do not have any lockers in the axles, it was an option and a highly coveted option because it will cost $3k+ to replicate that in an 80 that doesn't have them.

 

[ewillis]

So hi range on an 80 does not mean anything...what you are saying is that it is exactly the same thing as being in neutral...no gear reduction?

 

[Douglas S]

Neutral has nothing to do with it, but yes, there is no gear reduction in the transfer case in high range.

 

[powermad]

It is a full time 4x4, it's always in 4HI.
For your options you have high range full time. Front and rear always have power but the differential in the t-case allows you to drive it on the road.

When you shift into LO the center diff locks giving you equal power to the axles.
You can add in a CDL switch or a Hazard switch to be able to lock the center diff in high range.
The CDL switch was standard for 91 and 92 and an option for later years.

 

[scottryana]

No neutral means your are disconnecting your transfercase from any drivetrain power. In Neutral you will just sit there and rev.

 

[ewillis]

Neutral on the T=Case shifter is what I was referring to. The T-case is always in neutral unless you shift into 4 hi or 4 low...I was referring to the 4 hi vs neutral mode. I get the low and I get the neutral since that's what it's in when I'm driving, but the 4 hi is throwing me a curve ball.

 

[Timpanogos Slim]

4HI unlocked is basically what most people call all-wheel drive.

Which means that you are driving with one wheel on the front and the opposite wheel on the rear at any given time, and it can switch back and forth in no time flat.

when you lock the center diff, the rear and the front get the same amount of power all the time.

For about $300 you can throw an aussie locker in the back which will be nearly invisible during regular driving. And when you lock the center diff you will have basically 3-wheel drive - both rear wheels getting the same power as one of the front wheels.

on the front it is trickier. there is no LSD option for the front pumpkin that i know of, so it's either a factory e-locker, or an arb locker. auto-lockers like the aussie, detroit, etc are NOT recommended in the front because they can make the vehicle unstable on slippery terrain.

 

[ewillis]

The LC seems to move slower in 4 hi so I assumed there were reduced gearing at work.

 

[ewillis]

Thanks Slim...Aussie locker sounds kinda interesting, I thought it was ARB air locker or nothing.

 

[scottryana]

We need a pic of your trans shifter.

It should be 3 simple positions.

4H
N
4L

You should always be in 4H and pull the lever back through Neutral into 4L.

If you are always in Neutral you wouldn't go anywhere it is just the same as if you put your transmission in Neutral.

Not my pic but what I could quickly find.

Neutral on the T=Case shifter is what I was referring to. The T-case is always in neutral unless you shift into 4 hi or 4 low...I was referring to the 4 hi vs neutral mode. I get the low and I get the neutral since that's what it's in when I'm driving, but the 4 hi is throwing me a curve ball.

 

[Timpanogos Slim]

The LC seems to move slower in 4 hi so I assumed there were reduced gearing at work.

That's the opposite of making sense.

if the TC is in neutral, you aren't going anywhere unless you are on a slope or someone is pushing.

TC in HI is what you want on the road.

TC in Low is what you want on tricky terrain.

By default the F(Z)J80 TC locks the center in low, and does not lock the center in high.

If you install a CDL switch you can lock the center diff in high gear. You can also just use a hazard switch connected to the CDL switch harness. You can get hazard switches and CDL switches for <$50 here on 'mud in the marketplace forums.

Once you've installed the CDL switch, you can pull pin 7 out of the transmission ECU ("Pin 7 mod") and this will prevent the tcase from automatically locking the center diff when you are in 4-low.