3rd gen multi-mode explained.

[si tate]

[Ben_D]

Thanks for that Si, what is the book?

How do I know if my diff lock is working? My truck does everything except give me the orange light in the centre of the lit up pic on dash for the 4wd.

4wd button on lever engages 4wd (H4), lever moved down with or without button depressed gives me 4wd and lever shifted down (H4L). Down,to the right and up gives me 4wd low range (L4L).

I know thetruck goes into 4WD and low range when it is supposed to / says it is as its easy to tell when it is in 2wd. This is th first 4wd I have owned so not got anything to compare it to, I am concerned that the diff may not be locking as I get no orange light, is there any way to tell if the diff is locked or will it definitely be locked if box is operating as described as above, i.e could just be that the bulb is goosed?

Cheers

Ben

[si tate]

The book is from roughtrax "small hand book" as for the diff light i am not really sure mate but a transmission expert will be along soon enough.

[Scorpion]

Got a lot of useful info here when I asked.

[Ben_D]

Got a lot of useful info here when I asked.

Thanks Jim, read that and all other related threads. It is the lack of orange light that has me wondering. Truck goes into high range / low range 2/4wd as it should but I'm not getting the orange light to say the diff has locked when I select on of the "L" positions.

Looking for a physical way to check that the diff is locked, any suggestions?

Cheers
Ben

[KERRSURF]

Thanks Jim, read that and all other related threads. It is the lack of orange light that has me wondering. Truck goes into high range / low range 2/4wd as it should but I'm not getting the orange light to say the diff has locked when I select on of the "L" positions.

Looking for a physical way to check that the diff is locked, any suggestions?

Cheers
Ben

Drive really quickly on a roundabout with it engaged and see if anything breaks.

[BUSHWHACKER]

Thanks Jim, read that and all other related threads. It is the lack of orange light that has me wondering. Truck goes into high range / low range 2/4wd as it should but I'm not getting the orange light to say the diff has locked when I select on of the "L" positions.

Looking for a physical way to check that the diff is locked, any suggestions?

Cheers
Ben

Were you checking this with the truck stationary or rolling?

[Ben_D]

Were you checking this with the truck stationary or rolling?

Stationary to check what lights came on, then I drove around the farm with the lever in each position, (slowly) Only lights that come on are the green ones, no orange light for diff lock regardless of selector position. Green lights come on more or less instantly. Thinking about it, I did get stuck a while back (sank into a very muddy field) and had to be pulled out, farmer that helped me out said one of my wheels wasn't turning and I thought diff should have been locked. Was unaware of the orange light thing until today, I have never had it come on on my truck so maybe it has been goosed since I bought it.

Any suggestions for what I now think is a fault?


Cheers

Ben

[BUSHWHACKER]

Does yours have multi mode: H2, H4, H4l, L4l?

The centre diff should lock automatically as H4l or L4l is selected, and the orange light comes on.

Could be that there's a vacuum problem.

[Ben_D]

Does yours have multi mode: H2, H4, H4l, L4l?

The centre diff should lock automatically as H4l or L4l is selected, and the orange light comes on.

Could be that there's a vacuum problem.

Bushwacker.

Yep, multimode, exactly as above in Si's diagram. Only realised the orange light should be on when I looked at the youtube clip of that SSRG for sale in Ireland!!

Can you recomend a list of things to check, just about getting my head around basic servicing / engine stuff but no prior knowledge of 4wd transmission / locking diffs etc.


Cheers

Ben

[TonyN]

....I did get stuck a while back (sank into a very muddy field) and had to be pulled out, farmer that helped me out said one of my wheels wasn't turning and I thought diff should have been locked. ...

You will still spin one wheel on each axle even with the T/case locked. You don't have diff locks in the axle.

But light should be on, Its mechanically selected on lever, so check the bulb first.

The center diffl lock is pretty tough, if anything is broken there will be bits of teeth in t/case, with will make short work of the rest of it.

If the diff lock is working, on full lock on a hard surface the truck should feel like you have a wheel clamp on. Try it gently. If it just drives happily in a circle then t/case isn't locked up.

[Ben_D]

You will still spin one wheel on each axle even with the T/case locked. You don't have diff locks in the axle.

But light should be on, Its mechanically selected on lever, so check the bulb first.

The center diffl lock is pretty tough, if anything is broken there will be bits of teeth in t/case, with will make short work of the rest of it.

If the diff lock is working, on full lock on a hard surface the truck should feel like you have a wheel clamp on. Try it gently. If it just drives happily in a circle then t/case isn't locked up.

O.K, I'll try that. Thanks!!

Could you please explain to me what exatly locking the diff does? My current understanding is that when not locked it acts as a normal diff to allow one wheel to turn faster than the other for cornering etc. Locked means both wheels on the axle turn at the same speed having the implication of more or less overiding the diff. I expected that when stuck in mud all wheels would turn regardless when diff was locked. Sorry for the probably elementary question but I am new to the technicalities of 4wd, locked diff etc!!

Many thanks

Ben

[J i m s t e r]

Thanks for that Si, what is the book?

This 'un:
http://jpnz.co.nz/afawcs0131171/CATI...ctdetails.html

[TonyN]

O.K, I'll try that. Thanks!!

Could you please explain to me what exatly locking the diff does? My current understanding is that when not locked it acts as a normal diff to allow one wheel to turn faster than the other for cornering etc. Locked means both wheels on the axle turn at the same speed having the implication of more or less overiding the diff. I expected that when stuck in mud all wheels would turn regardless when diff was locked. Sorry for the probably elementary question but I am new to the technicalities of 4wd, locked diff etc!!

Many thanks

Ben

You are thinking of locks in the diffs on each axle, this will make both wheels on the same axle turn the same regardless of traction. This is a different thing. You don't have them.

You have a diff in the transfer case, so your truck is AWD, all full time 4wd trucks do, it lets the wheels on the front front and back axle turn at different speeds as you go round corners. It's why part time 4wd trucks like 2nd Gens and pickups can't use 4wd on the road.

But because you have a diff in the t/case, if you go proper offroading and get stuck, the diff in the t/case will act like the diffs in the axle, it will send power to the wheel with the least traction, front or back, but just one wheel!

So now you have to lock the diff in the t/case, to supply equal power to the front and back axles (not wheels, you still have open diffs in axle remember). Once your center diff is locked, you are the same as a part time 4wd truck in 4wd. Hense why you can't use center diff locks on the road. But you will get 2 wheels with traction, one on each axle if you get stuck.

Very few trucks are actually '4WD' Merc G-wagons come with front and rear lockers, Landcruiser Amazons are front and rear but only optional I think (but not sure), lots of Colorados have a rear diff lock. Disco's, Range Rovers, older Shoguns, etc... are all AWD but no axle diff lock options from the factory, same as 3rd Gen Surfs.

Newer stuff is different, this mostly applies to upto 2000 year trucks, not had much to do with newer trucks.

[Apache]

My current understanding is that when not locked it acts as a normal diff to allow one wheel to turn faster than the other for cornering etc. Locked means both wheels on the axle turn at the same speed having the implication of more or less overiding the diff.

Only in an axle diff lock. The centre diff lock means front and rear DIFFs are forced to turn at the same speed. It has no effect on the wheels across an axle's ability to turn independently.

Rear diff locked - both rear wheels forced to turn at the same speed.
Front diff locked - both front wheels forced to turn at the same speed.

Rear, front AND centre locked, ALL wheels forced to turn at the same speed.

<edit> Tont beat me by seconds - BTW, Andy Boyo's 'cruiser has front, rear and centre lockers - the monster that it is!