AWD to part time 4wd

[dean1kz Lurker Find all posts View Profile Close dean1kz]

Hi,
I own a "gray-import" 1997 KZJ95 3.01KZTE A/T with AWD. Transfer case got 3 choices; HH, HL, LL.

As worlds known that AWD will guzzle fuel, I plan to convert to part time 4wd without eliminating the HH function, is it possible?.
As what we have in HILUX SURF (4 Runner) transfer case, 2H to 4H(HH) can be switched by pressing a button while center diff in unlock.
Centre diff lock will only activate at HL (center diff lock-high) and at LL (center diff lock-low).

Any possibility to do that?

to all gurus out there, any advice & helps would be much appreciated.

[zookcubr Senior Member Find all posts View Profile Close zookcubr]

I know they make a part time kit for 80 and 100 series, but alas not the Prados. Its a shame though, you'd think they would sell a few. Not sure about the other idea though.

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Welcome to the forum.

This topic has been covered before.....

Yes you would need the late model 1kz Surf transfer case and a set of free wheeling hubs (Which don't just bolt on by the way)

It's doubtful you would save enough fuel to pay for the parts, modifications and labour on this conversion.

A dump pipe, straight through muffler and mandrel bent exhaust is a better option.

Some owners who have fitted piggy back style ECU upgrades (Dtronic/DP chip) have also reported fuel savings (me included)

Save around 1+ lt/100 km with exhaust and up to 0.5 lt/100 with the chip on the 1kz.

More power to boot too....

Mick

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Also forgot:

You can also fit a UniFilter/Finer filter (oiled type foam air filter) for a little more and as you have a 90 series some gains can be made by tidying up/ shorting the intake pipe work.

Mick

[dean1kz Lurker Find all posts View Profile Close dean1kz]

hi MickL & zookcubr, thanks for your reply.

too bad there're no parttime 4wd kit for 90series..

i just wondering, malaysia's version prado GX have part time 4wd transfer case (lever operated), but i don't know whether it got selection 4H (center diff-unlock)_ 4H (cntr diff-lock)_4L (cntr diff-lock)

can i just swap it? any modification needed? any electrical thingy need to take care? any other mechancal thingy need to be customized??

really blurr here... :?:

[MickL Addicted PP Member Find all posts View Profile Close MickL]

If it's from the same series and spec vehicle I would imagine in would bolt straight in.

We don't have a part time GX Prado in the Australian market. The Australian GX is AWD also.

On the Surf there is a button to engage 4wd/2wd (connecting/disconnecting the front diff) then H/HL/LL is via a conventional lever on the floor.

I have extensive knowledge of this set up... you won't save enough fuel to even notice let alone save fuel. Because only the diff is disconnected the front shafts keep turning so you still have drive line drag.

You would have to fit manual (Or auto hubs) to the front wheels to gain full benefit and even then the fuel saving is doubtfull in my mind.

The mods I have mentioned would be more cost effective, and they are tried and proven...

Mick

[dean1kz Lurker Find all posts View Profile Close dean1kz]

On the Surf there is a button to engage 4wd/2wd (connecting/disconnecting the front diff) then H/HL/LL is via a conventional lever on the floor.

I have extensive knowledge of this set up... you won't save enough fuel to even notice let alone save fuel. Because only the diff is disconnected the front shafts keep turning so you still have drive line drag.

mick, to be honest i'm newbie on this 4wd SUV/trucks...

your info about surf drive train impressed me, eager to learn more from you.

refer to surf transfer-case; when 4wd button is pressed (4h) how about the centre diff? is it straightaway lock or need to push lever to HL?

about the 4wd lever, all this while i thought whenever vehicle is operates on 2wd mode, transfer case disconnects front prop-shaft, power transmit direct to rear prop-shaft. While front axle is still connected to prop-shaft and turns freely... am i right?
or there is another mech things that disconnect prop-shaft connection inside the front axle??..

as mentioned by you about the mod;

...A dump pipe, straight through muffler and mandrel bent exhaust is a better option....

Some owners who have fitted piggy back style ECU upgrades (Dtronic/DP chip) have also reported fuel savings (me included)....

You can also fit a UniFilter/Finer filter (oiled type foam air filter) for a little more and as you have a 90 series some gains can be made by tidying up/ shorting the intake pipe work....

do you hv any details/pics of these? i doubt we (in malaysia) have such kind of things..high tech engine mod..elctronics things...piggy back style ecu for 1kzte.... FYI too bad, here they more concentrate to body kit mod, lift-up and conventional mech mod..

no doubt, there's a lot of land-cruiser i found in aust during my last visit to frementle & perth..

[waltec Senior Member Find all posts View Profile Close waltec]

The difference between these 2 transfer cases is only in operation not in funtion, the Surf has a lever H & L plus a 4X4 switch, prado has just the lever with 3 positions HH (2H), HL (4H), and LL (4L).

SURF Prado
H+4x4 off HH High Range centre diff unlocked (AWD)
H+4x4 on HL High Range Centre diff locked (4WD)
L+4x4 on LL Low Range Centre diff locked (4WD)
L+4x4 off -- Low Range Centre diff unlocked (AWD) Handy for slow manuvering of trailers.

As you can see there is realy no difference between these traansfer cases.

A true part time 4x4, has front hubs that disconnect (manual or Auto) and a transfer case that also disconnects the front drive shaft.

As others have stated its not the AWD that guzzles the fuel its the fact thats its a 2ton vehicle that your trying to move that takes quite some energy (fuel) to get moving.

More on Trojan's post, I had a friend how owned an old 80series (barn doors and grey wheels, they were part time 4x4, but the front hubs were not free wheelers (was an option). His wife was the main driver (school bus during week, was bought to tow horse float), he keep accurate fuel records. He was convinced that fitting free wheeling hubs would lower fuel consumption (you would try anything to reduce fuel in these old petrol motors). Fuel consumption was unchanged by this. This was probably a true test as the wife had no preconcieved idea (so no placebo effect) as she had no idea of the hubs, she just drove it and put petrol in it.

Matt

[MickL Addicted PP Member Find all posts View Profile Close MickL]

When you get down to it, there is massive debate as to whether there is any benefit to converting a 80/100 Landcruiser to part time. Most data about shows it's a waste of time if you're chasing fuel economy

That's true, the original idea behind the conversion was not for economy but to remove the excessive drive line backlash on awd 80 and early 100s.
A claim of improved fuel economy was added but minor benefit (claims up too 10% have been made)

Toyota have improved their AWD drive trains a lot and the backlash was no longer an issue after the early 100 series came out.


To convert an AWD to a part timer you need to remove the centre diff and fit a solid spool. You also need a set of free wheeling hubs fitted.
The centre diff lock then activates 4wd (hubs locked in of course).

Mick

[Jam Junior Member Find all posts View Profile Close Jam]

Re: AWD to part time 4wd

I plan to convert to part time 4wd without eliminating the HH function, is it possible?.

Hi,

My two cents worth... You can buy a lot of fuel with the amount of money you would spend on any part-term kit or a new transfer case.

Whatever you do, don't do what I saw a fella with an 80 series do: he put AVM hubs on the front and unlocked them, then left his center diff lock on permanently...

Best of luck

Jam.

[boof Member Find all posts View Profile Close boof]

Re: AWD to part time 4wd

I know this is a bit of a dig but in researching my own needs I may have come across a way for this to be possible?
The new hilux runs a passenger drop case, the SR runs full time locking hubs but 2wd availability, I know they would bolt up to the 120 gearbox as they are the same, but they may also do so in the 90s, might be worth a look if you really wanted part time 4wd 8)

[KZJ90 Member Find all posts View Profile Close KZJ90]

Re: AWD to part time 4wd

Full Time 4WD was the Big + when I was considering of purchase LC 90-series. I have liked it much, although I know it might take about 1 l/100 km more than driving with 2WD. I had 4Runner with same engine, it was about 200 kg lighter and with free-wheeling front hubs. It took about 9-9,5 l/100 km, my 90 takes 10-10,5 l/100 km.

[MRW82 Member Find all posts View Profile Close MRW82]

Re: AWD to part time 4wd

so does anyone know a way to have the centre diff lock so you can manually operate it? so you can get lowrange centre diff unlocked.
I want it so I can reverse the trailer up my concrete driveway (slight uphill slope) without having to ride the clutch.

Mark.

[KZJ90 Member Find all posts View Profile Close KZJ90]

Re: AWD to part time 4wd

so does anyone know a way to have the centre diff lock so you can manually operate it? so you can get lowrange centre diff unlocked.
I want it so I can reverse the trailer up my concrete driveway (slight uphill slope) without having to ride the clutch.

Mark.

How about Free Wheeling Hubs? When open, you have to drive the centre diff lock locked, works with 4L too. And when full-time 4WD is needed, just lock the hubs.

[dhula Member Find all posts View Profile Close dhula]

Re: AWD to part time 4wd

so does anyone know a way to have the centre diff lock so you can manually operate it? so you can get lowrange centre diff unlocked.
I want it so I can reverse the trailer up my concrete driveway (slight uphill slope) without having to ride the clutch.

Mark.

A while back I looked into this but no deeper than looking at the t'case schematics. I never pulled anything apart.
At the time I thought it might be possible to do a twin stick conversion to the t/case but at what cost I don't know.
There would have to be custom shifter levers made and a new top plate for the t'case perhaps as the shift forks look to be in the case instead of external like some other t'cases.