4X4 Problems

[WEDMAN]

1995 Toyota T100 DX auto trans, 3.4L V6

New here. I have found a lot of useful info already. Let me know if this post belongs somewhere else...

The T100s 4X4 indicator lights are not working and I'm not sure if 4WD is functional at all. Have done some fiddling - please advise.

In 2WD - Front driveshaft spins freely by hand.

Put truck in 4HI and 4LOW - Front driveshaft cannot be turned by hand.

At VSVs - Brown nipple has vacuum in both 2WD and 4WD, blue has vacuum in neither. No voltage at blue VSV connector. +-12V at brown. There were mouse droppings in the glovebox when I bought this truck, hoping they didn't go nuts on the wiring. Not sure where to go from here.

I do not own a FSM. Thanks in advance.

 

[541joseph]

Might have better luck in the 3rd gen section

 

[KidVermicious]

1995 Toyota T100 DX auto trans, 3.4L V6

New here. I have found a lot of useful info already. Let me know if this post belongs somewhere else...

The T100s 4X4 indicator lights are not working and I'm not sure if 4WD is functional at all. Have done some fiddling - please advise.

In 2WD - Front driveshaft spins freely by hand.

Put truck in 4HI and 4LOW - Front driveshaft cannot be turned by hand.

At VSVs - Brown nipple has vacuum in both 2WD and 4WD, blue has vacuum in neither. No voltage at blue VSV connector. +-12V at brown. There were mouse droppings in the glovebox when I bought this truck, hoping they didn't go nuts on the wiring. Not sure where to go from here.

I do not own a FSM. Thanks in advance.

Maybe you already know all this, but a couple different things happen when you shift your tcase lever to 4wd. First, the collar in the transfer case physically engages the gears running to the front driveshaft. That's why you can't spin that DS when you've selected 4wd - it's tied to the drivetrain. So that part is good. The other thing that happens is the ADD setup uses vacuum to actuate a slide collar on the long-side half-shaft, which lets the front diff put power to both front wheels. If you'd like to test whether that's working or not, jack the front of the truck in the air and put it in 4wd, then try to spin each tire. If the drivers side tire spins freely and nothing else happens, that actuator isn't engaging. If the passenger side tire spins in the opposite direction that you spin the drivers side tire, then it's working. As far as vacuum goes, I'm not up to speed because I've never had an ADD truck, but I believe you should have vacuum on one side in 2wd and vacuum on the other in 4wd - if that's not switching when you engage the tcase lever, maybe you found your trouble?

The 4wd light in the cluster could be a burned out bulb, or a bad sender, or a sign that the front actuator isn't working. Check the 4wd itself, then you'll know if you're chasing an indicator issue or a 4wd issue.

You should find a link to download FSMs in the stickies at the top of this forum. Been a while since I've looked at that site, but I think there's a T100 manual there. If not, your front suspension/4wd components are very similar to the second gen 4Runner, and your 3.4 drivetrain is the same as the third gen.

 

[9494runner]

I had a similar problem with my '94 ADD system. throw the truck into 4x4 and the light would flash 4-6 times very fast, after randomly trying to engage 4x4 a few time with fingers crossed the light wouldn't turn on any more but i would still hear the click behind the dash, indicator switch was getting power . ended up having to go completely thru 4x4 vacuum system and that solved the problem. I apparently had a dangling vacuum line and when i had it serviced they plugged the line in the wrong nipple, not exactly sure how this happened but it solved the problem. If you have a 3rd party ADD switch on your front diff this can also lead to problems. i switched mine, it had a Dorn (purchased from auto zone i think) part number on it. the one from the parts store leaked badly and was not showing the proper resistance on the volt meter.

Just based on my experience with my ADD system i would trace all of your vacuum lines back to make sure they are not cracked or in the wrong place FSM vacuum diagram kinda is a drag but it will help you get the job done!

 

[fourwd1]

There's a switch on the ADD actuator on the front axle to report that the axle is locked and one (or more) in the t-case to report 4WD mode. Both are required to light dash indicator.

 

[Hyde802]

Might have better luck in the 3rd gen section

No hes good here. The only thing a t100 shares with the 3rd gen is the rear 3rd.