4x4 Issues. Front Not Working

[PrinceYota]

I have a completely stock 2000 4Runner 3.4L V6 Auto with ADD and my brother took my Runner for the weekends to go hunting. He said the front was not spinning at all. 4x4 Indicator light came. If the indicator light comes on when engaging it to 4H or 4L then the rod in the front differential actuator shifted to turn on the indicator light. Therefore if the rod moved then the fork would've moved with it to move the sleeve to lock and unlock. Someone please tell me what can cause the front not to engage? How can I test to confirm the front is not working besides taking it off road? I've had this issue before but thought I fixed it. I replaced the actuator but never took it off-roading to test it apparently that didn't fix it.

 

[KidVermicious]

How can I test to confirm the front is not working besides taking it off road?

Four jack stands.

 

[Robb235]

If you engage the 4wheel drive, can you spin the front drive shaft freely by hand? Or does it not rotate?

 

[tre9er]

Four jack stands.

Or throwing it on a lift.

 

[TheDurk]

If you engage the 4wheel drive, can you spin the front drive shaft freely by hand? Or does it not rotate?

That won't tell you anything, because the shaft will lock from the t-case side even if the diff does not engage. The system is designed so that the front diff does not engage UNLESS the t-case is already engaged. What you CAN do, is leave it in 2wd, switch the two hoses coming up from the front diff to the VSV's, and start the engine. Drive it back and forth a little to give it a chance to engage. This should cause the shaft to lock without the t-case engaging, and thus show all is well in the front.

Remember to switch the hoses back.

Although you can tell if you are in 4wd, by just driving a little on asphalt in 4wd. It will fight you on the turns. Just low speed for one minute in a parking lot won't damage anything.EDIT: I mean real 4WD not AWD--I'm not a slushboxer, so these distinctions escape me.

 

[tre9er]

Although you can tell if you are in 4wd, by just driving a little on asphalt in 4wd. It will fight you on the turns. Just low speed for one minute in a parking lot won't damage anything.

I can attest to this. The other day after I greased all my drive shafts and ujoints I put it in 4H for a minute to get things moving and it fought me hard turning out of the driveway. I freaked out, thought I had hit center diff lock...

 

[Robb235]

That won't tell you anything, because the shaft will lock from the t-case side even if the diff does not engage

Oops. Guess I misunderstood the question.

 

[snivilous]

I can attest to this. The other day after I greased all my drive shafts and ujoints I put it in 4H for a minute to get things moving and it fought me hard turning out of the driveway. I freaked out, thought I had hit center diff lock...

If the center wasn't locked then it shouldn't have fought you... Is there some reason you don't have full time 4WD (AWD)?

 

[tre9er]

If the center wasn't locked then it shouldn't have fought you... Is there some reason you don't have full time 4WD (AWD)?

I've never really understood this. I have a 4WD shifter in my 4R that can be put into either 4H or 4L. It sits in 4H by default. On the side of the shifter is the 4WD button. I engage it when I go off-road, and then the lights in the dash flash until it's engaged.

I was under the assumption that without the button pressed, and the lights on the dash lit up, that I wasn't going to get the front wheels turning under power, whatsoever...is this incorrect? Or what is everyone referring to with this AWD stuff? I thought I had traditional 4WD that required activating in order for the front wheels to receive any power from the tcase.

 

[snivilous]

I've never really understood this. I have a 4WD shifter in my 4R that can be put into either 4H or 4L. It sits in 4H by default. On the side of the shifter is the 4WD button. I engage it when I go off-road, and then the lights in the dash flash until it's engaged.

I was under the assumption that without the button pressed, and the lights on the dash lit up, that I wasn't going to get the front wheels turning under power, whatsoever...is this incorrect? Or what is everyone referring to with this AWD stuff? I thought I had traditional 4WD that required activating in order for the front wheels to receive any power from the tcase.

You're correct that when you press the 4WD button on the side of the shifter the transfer case is now putting power to the front differential. However, just like the left and right tires spin at different speeds on corners (what a differential compensates for so they don't fight each other), so do the front and rear tires in relation to each other. Because of this, the '01 and '02 (not sure if the '00) have a 'center' differential in the transfer case.

A "conventional" 4WD system doesn't have a center differential, so when 4WD is engaged the truck will buck because the front and rear axles are forced to spin at the same speed. With the center differential "open" (when the light in the middle isn't orange of the 4WD indicator) the front and rear can slip a bit in relation to each other, just like the left and right tires due to the front and rear differentials. So AWD (aka Full Time 4WD, etc.) is just having the front, center, and rear differential open so all tires can slip/spin at different speeds in relation to each other so it doesn't buck. When you lock the center differential, now the truck acts like a true 4WD and you will have slightly more traction and shouldn't be driven on pavement in more than a straight line.

So technically, you should have 2WD (all lights off), AWD (tires lights illuminated), and 4WD (center differential locked and all lights on). Hope that was a good explanation.

 

[tre9er]

Yes, excellent, thanks. I guess I think of AWD as "always on", so that's why it was confusing me.

I may have hit the center diff lock the time it was binding. It's good to know what the indicator lights mean, though.