mtpktz.

Where is the second line? I only pulled the one in the front.



Thanks for all your help.

3w41d

no the lines are on the add actuator which is attached to the front axle next to the differential

3w41d

a Haynes manual is one of the best things i ever bought for my truck

mtpktz.

Oops, I just went by the picture that somebody posted earlier in the thread.

I guess I'll just be picking up a manual. Thanks again for your help!

speltwrong

I had the same problem, I did an engine swap and the vaccum lines to my ADD were reversed. Toyota fixed the problem with no charge.

mtpktz.

I just remembered that I had my tires rotated right before this problem occurred. Any chance that has something to do with it?

*UPDATE*

After playing with some of the vacuum lines in the engine bay, I started the car up and 4H engaged and the dash illuminated the 4WD symbol. However, now there is a loud clicking when I shift from 2H to 4H coming from the right side of the engine bay (It sounds like it's in the glovebox). Is this normal? Maybe I just never noticed it before..

Thanks again guys!

Ogredaddy

Hi Howdy!

I posted this in the earlier model thread as well.

After reading every thread I could find on the issue, I figured it was vacuum or electrical related because the system was working fine 2 weeks ago.

Toyota was estimating $900.00 for the actuator or possibly $600.00 for the servo, plus labor.

The Actual Problem was that while attempting to get my truck through EPA, I had removed and cleaned the 1 way vacuum valve to the left of the battery and unknowingly re-installed it upside down - (White UP) Doh!

Here it is shown back to correct position - Black UP!




I took my truck to a recommended shop here locally and told them everything I had done recently, so they knew where to look.
Tah Dah!!! After confirming the system engaged fine when
vacuum was applied, The tech turned the valve back around to the correct position and 4WD was fine again.

If this valve is clogged it could cause the same problem, so
for systems not engaging or stuck in 4WD, this is the first place I would look.

The mechanic bookmarked this site for future reference
after I told him how much information was available here.

archer1965

I have the same problem with my 96 Taco, 3.4L, 5-speed, push-button 4X4.
This thread was very helpful in solving the problem without doing anything but checking vaccuum lines.

Same deal, one-way valve was clogged. Problem solved.

Fink

Awesome!

Can't tell you how great it is to see people actually searching and solving problems!



Fink

99yota4

I'm having the same problem and I have not had time to figure it out completely. So far what I know is that my ADD actuator is good and the VSV is good. I have the same symptoms as the OP, and as I took it to a shop, a friend there tried switching the hoses on the VSV and 4wd engaged! but no light on the dash. I'm thinking its electrical, but I don't know how to check it. Can anybody help? I'm assuming that when there was a motor swap, (previous motor started knocking because of lack of maintenance by previous owner) the transmission was moved around and some wires were snapped?? Where and what switches do I check and how do i check them? Pictures would be awesome with some info! Thanks!!