Marius193

Hey guys,
I'm working around my truck for 4 weeks now, including new head, new battery etc.
My actually problem is, that my 4x4 is not engaging.
When I first turn the key and then press the button, I can hear the Relais klicking 1 Time and that's it. No more klick, even in H and in L4.
What I did so far:
- Checked Switch on the H-L4 lever, jumped it because it wouldn't hold a permanent connection.
- check the Relais ( works okay as far as I can say)
- Checked the dash light (is working)
- Checked the switch on top of the transfer casing (is working)
- the cables to the vacuum valves are okay
- I have vacuum at the front axle

I'm running out of ideas

it's a Toyota 4Runner 1990 Manual 4x4 22R Engine 488000 km

I read through about 100 posts in this and other Forums.

I'm thankful for all suggestions!
Cheers Marius

millball

If you have vacuum at the front axle on the side of the ADD servo that engages the ADD, the 4WD light should light on the dash if ADD engagement is actually ocurring..

You ought to be able to determine if the ADD is engaging by jacking up one front wheel and trying to turn it when 4WD is selected,

If the transfer case is in 4wd and the ADD has engaged, the wheel should be imobile, and the front driveshaft immobile as well.

With both front wheels off the ground, with 4WD engaged, the front driveshaft should be imobile and when one front wheel is turned, the other one should revolve in the opposite direction, assuming open differential.

Marius193

Hey,
thanks for the fast reply!

I tried it like this:

swiched the the vacuum hoses at the front axle, jacked 1 Weehl up. Gear in L4 and neutral. I can turn the wheel and the drive shaved was moving as well. With both wheels on the ground the shaft was not turnable.

Sounds right to me or?

-----
I also found 2 Vacuum hoses going into the left hand fender. Where are they going to?

edit: they go to the vacuum tank
-----

millball

The driveshaft should not ever be able to be turned when the t-case is selected to 4WD, hi, or low. ( and tranny in any gear)

It should be locked rigidly to the T-case gearing.

Sounds like the ADD itself is working when vacuum is correctly applied.

Problem likely in T-case itself.

Marius193

I went to a local workshop to lift the hole car,
with the result:
The transfercase is not working at all. There is a separate Vacuum pump mounted on the back side. And it's not working. Mainly because it don't get any voltage from the system.

millball

You said in your first post that your machine is a 1990 4Runner 4 cylinder manual.

It should have no such vacuum stuff on the transfer case.

Your machine should have a RF1A gear driven case that is manually shifted.

millball

Wait a minute, I have assumed that you have a machine made for the North American market.

Some quick research haas shown me that there are indeed some electricly shifted RF1 type cases.

Please tell more about your rig and your location. Is it a diesel??

Marius193

what do you mean with rig?
I'm having fun with this baby in Australia ATM.
No it's a basic 22r Petrol No turbo

as far as i can tell, there are 5 cables, 3 for the pump and 2 for a sensor or something similar.

millball

Rig is an American slang for truck.

No American type manual tranny 4Runners use your pushbutton shift transfer case.

I don't know what to say about troubleshooting your problem.

You'll have to find a proper wiring diagram from a 1990 Toyota factory Service Manual

Marius193

Ah okay :-)

well thats the next Problem, I can't find one. I only have a Haynes but the don't tell anything about it -.-

Marius193

Anybody else some ideas?

Marius193

Okay, I found the Problem.
Bad connection on the 4WD position switch.
i removed it, cleaned the switch it self and the connectors. After that it worked.

millball

Glad to hear that you fixed it.

Most Americans are not familiar with the setup your truck has. Sorry not to be of more help.

70elcoss

i have a similar issue but on my v6 4runner. 5speed ADD, open diff but i think my issue is electrical because when i shift the transfer case into 4hi or lo i do not hear any clicks from the relay. 4wd light also does not turn on. anyone know where to begin troubleshooting?