4wd issues

[Paul ssrg]

Hi Guys,
New to the group.Iv recently bought a 1993 SSR-G,2LT with manual box.My issue is the 4wd system,or should i say lack of!The button on the small shifter doesnt seem to be doing anything.Iv tested the actuator on the front diff by switching the vacuum lines around on the VSV's on the drivers side valance.Jack up the front left wheel,switch the pipes over and give the wheel a spin and i can see the front prop spinning back to the transfer box.Disconnect them and the wheel is free spinning again.So then i thought the switch on the lever maybe be faulty...pulled out the connector and bridged it with a piece of wire but to no avail.Any insight guys?could it be the 4wd ecu/relay that i hear clicking under the dash?
Iv tried putting the lever in 4L,and driving forward and back to engage.In 1st gear the revs are high,as if it has geared down but im 99% sure its still in rear wheel drive...if thats possible?!Also when i move the lever from low to high range or vice versa,there is a noticeable click sound coming from the top of the gearbox.

[andyverran]

Does the actuator on the transfer box engage?

[Paul ssrg]

Im not sure...how can i tell?the only thing i know is that the front prop is free spinning back to the transfer case when the front hubs are locked

[BUSHWHACKER]

Sounds like the actuator on the transfercase isn't fully engaging. Press the button and drive forwards or reverse and see it it locks the front prop.
Does the green 4wd light on the dash illuminate?

[Paul ssrg]

No im getting no light on the dash either.some websites i was researching on mention a 20amp 4wd fuse,but i cant for the life of me find it!

[BUSHWHACKER]

No im getting no light on the dash either.some websites i was researching on mention a 20amp 4wd fuse,but i cant for the life of me find it!

You say you can hear the 4wd relay clicking and a noise coming from the gearbox, this means the fuse is OK.

If the light isn't coming on then the actuator on the back of the transfercase isn't fully engaging the front prop. There are limit switches on the side of the transfercase that activate the green light when the relevant gears are meshed to engage the front prop. There's also a limit switch on the front diff.

Just drive forwards or backwards a few meters to see if 4wd engages.

[Paul ssrg]

Yes there is a definite click from the under dash area.the noise from the gearbox appears to come from behind the shifter position where there are two switches/sensors close together.which should switch first,the transfer case of the vac switches in the engine bay?

[BUSHWHACKER]

Not sure, I think they should all switch at the same time.

The 4wd relay is above the throttle pedal.
The 4wd control box is behind the ashtray/cig lighter.
The 4wd fuse is behind the panel next to the throttle pedal.

Here's some info on the A.D.D. system for the 2nd gen Surf/4Runner.....
http://www.toyotasurf.asn.au/techsite/add.htm

There's a wiring diagram/PDF file the the drivetrain section here......
http://www.toyotasurf.asn.au/techsite/downloads.htm

[Paul ssrg]

Tried driving it forward and back today with the lever/button engaged but havent gotten any further along.would that point towards more mechanical than electrical issue?

[BUSHWHACKER]

Tried driving it forward and back today with the lever/button engaged but havent gotten any further along.would that point towards more mechanical than electrical issue?

If the vacuum side of things is working OK then I would say the actuator motor on the transfercase is faulty.
The most common thing to feck them up is dislodged or missing breather pipes on the transfercase allowing water ingress.

You can eliminate the troublesome vacuum part of the A.D.D. system by following this......
http://www.hiluxsurf.co.uk/showthrea...ht=troublesome

[Paul ssrg]

Cheers for the help.im gonna tackle it next time iv some free time at the garage!