4wd wont disengage

[timwande]

i have a 1989 fj62 and the the 4wd green light wont go off. the hubs are in free position and i transfer case is set to H2. around 55-60 mph it starts to humm a lot. i have pushed the switch to the off position and the light stays on. i'm pretty sure the 4 wheel drive is engaged. any suggestions on what i can check for to correct this problem. thanks.

 

[Sir_Titus]

have you been running alot of mud?

 

[yooper]

First, lock your hubs - you'll never be able to switch out with them free. The truck has to be moving and the hubs have to be locked in order to switch out of 4WD and sometimes you need to get up to speed a bit and let off the gas pedal and coast a bit.

The 4WD switching is vacuum-actuated. There are two vacuum solenoids on the firewall next to the heater valve. This is most likely where the problem is - probably one of them has failed. You can try reversing the vacuum hoses from the engage solenoid to the disengage solenoid and it might switch out for you. You can find junkyard replacements for the valves from lots of other Toyota vehicles - they were used as part of the A/C system on vans and Corollas. Search the archives of the 3FE list and you'll find lots of discussions of this issue: http://www.birfield.com/archives Better yet, join the 3FE list and read the writeups in the files section about it. http://autos.groups.yahoo.com/group/3FE/

You can also buy the valves from Mac. Here is that info from the 3FE files section:

Fix for Vaccum Selonoid Transfer Switch
By Keil Thompson

Here is the solution if your vaccum selonoid fails:

Parts:
mac 35a-aaa-ddba-1ba valve 12v 2 each total $ 34.00
arrow asp-1 exh muffler 2 each total    3.20
28-4-2 parker fitting-qty 4 each total 0.44
Grand Total for two complete valve assemblies  $39.64

Installation:
The mac valves have three slots for the fittings.
I used teflon tape to get a good seal.
The exhaust fitting goes in the top numbered 3.
Install the parker fittings in the other two screw intakes>
The line from the manifold goes into the fitting that is marked 1
on the mac valve.
The line from the transfer goes into fitting marked 2.
Cut the old wire leads off and connect the mac valve leads
connect the vaccum lines.
I formed a mounting bracket out of aluminum.


To find mac valve dealer go to www.macvalves.com
I got mine here in ga. from tsi solutions 770-879-3500 but i think
that they only sell in georgia

 

[Dan_J-spec_fj62]

Tim,

One quick way to check weather or not you are in 4wd is to grab your front diveshaft and see if it spins freely.... if it does you are not in 4wd. Word of caution don't do this with the vehicle in neutral on an incline... bad things will happen!!!

usualy only one of the vaccume switches craps out at a time... so when you switch the vacccume lines (the bottom ones) push your 4wd switch to the "on" position. it should disengage. the junk yard is a good place to find the switches I got a set for $10 when I had to replace mine.

good luck and welcome!!

dan

 

[dd113]

All the other posts are correct. One additional thing: dont believe the switch light. Get under there on a steep slope w/o the P brake on and in neutral and see if the ft shaft will turn. NO really, just see if the shaft will turn. If it does and the light is still on disconnect the switch on the ft end of the TC. Not too expensive new or used.