My Part time 4wd conversion

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

So some may know I picked up a multi mode transfercase from a 185 surf a few months ago but was missing the 4wd actuator
Today I picked up a actuator so in the next few weeks I will be swapping this out
It's going to need the shaft lengths changed
Then need to work out how to wire this motor in , I have a few ideas they bassicly have limit sensors in them the 4wd ECU swaps polarity
Last sub tank took 56 lt and that got me 500ks !! About 11.2 lt per 100k so I'm hoping in part time I can get that down to 10 ... Almost into D4D economy figures on a std engine

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

I fitted my part time case today went in with no hassles everything just bolted up
It extended the driveline by 50mm so rear shaft gets cut down 50mm and front extended 50mm
The 185surfs use a different 4wd ecu but I think I an make the 90 prado 4wd ecu work
The 185 surf range selector bolted up in the correct position only being a little lower than normal witch I like
So normal driving around town will be in 2wd , if it get crappy and wet and the missus is driving I can select 4wd with center diff free
Then 4wd center diff locked and 4wd low range lock
4wd is activated by a button on the side of the selector

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

Awesome - I'm very interested in this mod!

Which engine and transmission do you have? (directly affects ability to bolt transfers up)

How are the shafts shortened/extended?

What is the important of ECU control of 4wd? I mean, what does the ECU actually do for it - I didn't think there was anything electronically controlled other than the light in the instrument cluster.

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

Any toyota 300 series trans will bolt up
But you do need to use the transfer case adaptor ( the alloy joiner that goes between the back of the box and the case)
The new transfercase is 50mm longer so the shaft flanges are 50mm further to the rear
The 4wd ECU is completely seperate from the engines ECU it controls the 4wd activation motor on part time Toyotas and on Prados with electronic center diff lock it controls that
It's little more than a relay box

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

Oh and Iv got a 95 series with 1kz auto
I'm thinking about the ADD diff from the front of a surf ... This will allow me to disconnect one cv stopping the diff and front tail shaft from spinning up reducing my fuel further I hope

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

Well finaly got it working correctly today ! I thought the centre diff was locked as I couldn't unlock it when in 4wd .... Turns out the CDL isn't manually actuated ..... It's got a switch that when you pull the lever down for CDL it makes the motor rod slide a bit further I didn't know this
The actuator controls 4wd AND the Centre diff lock
There very common in the USA std fitment in the tacomas and some Tundras...
The transfercase is called a "VF3AM" and is based of a VF2A
If you have a diesel 90 this will bolt straight in tail shafts and everything, this is because the diesel box sits further back than the V6 (torque converter longer in diesel)
Another feature is the center diff is a "Torsen" diff meaning it is a 40/60 ratio rear being more power until it detects the front slipping then instantly gives more power to the front

Also while searching I believe the Tacomas have the same basic chassis as a 90/185 surf and they come with free wheeling hubs ! .... Wonder how much they would be to get a couple of hubs over...?

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

I also had to fool the 4wd ECU into thinking the front diff had engaged...... The fact that it always locked on the prado but the surfs have the ADD front diff I just put a relay in ....the ECU just needs a wire to ground when the diff engages piggy backed a relay from the 4wd button and done !
Only bad point so far is I can't select 2low , I can put a 4wd cancel switch in ,then this will stop the actuator moving so then when I shift the lever to low drive it will still be in 2wd

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

So i got annoyed at the front diff constantly spinning creating drag so i bought a KZN185 surf front diff with the ADD system (auto disconnecting diff) fitted it up litteraly bolted straight in it has 2 vacuum hoses going to it to engage/disengage
Hoping it might drop my economy
Either way i have a fully converted part time 4wd prado now
Shes bloody loose in the wet ! Full time 4wd engaged is a must in the rain ! Unless fun time is on the cards

[raydes Advanced Member Find all posts View Profile Close raydes]

I have to ask WHY???? you must have to much money or time or both...lol

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

I have to ask WHY???? you must have to much money or time or both...lol

Why not ???
How much do you think it cost? I also converted the car to diesel

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

Nice one! Careful with front drive strain, I believe the ADD adds a little weakness..?

I'd still like to convert mine to part time but never had luck finding an easy drop in transfer solution.

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

Iv had a add surf before and never had a problem infact i welded a front surf diff up then twisted the cv joint off
I dont do a great deal of hard stuff anyways
If your interested in a part time case (multi mode) i know where there is one youd need case 4wd ecu at a minimum

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

hey Scott yeah I'm interested, pm sent