cbohannan1985

My 90 4 runner with a auto V 6 doesnt engage the front axle when going into 4x4, I cant find a diagram of the front axle in my chilton can any one help me thanks

fireman1559

how do you know its not engaging? not but really do you have ADD or manual hubs? if you have ADD check VSVs and all vaccum lines and the front actuator on the front diff.

fireman1559

and welcome to
YOTATECH!!!!

cbohannan1985

i have ADD hubs but i dont have a diagram for the vaccum lines or the digram for the axle the prior owner said it was a actuator tried climing a mountion and all that would spin was the rear tires

cbohannan1985

can u help with the diagrams

fireman1559

at one point i could have but i cant find anything but how to take apart a manaul hub. the only thing i can say to do is follow the lines if it is like my pickup was you should have a tank in the passenger fender well for the front diff and the lines will run under the hood to the passenger side where the VSVs will be and they are if i remeber green and blue and those should be set to a certian voltage other than that its all electrical. but what i did was permentaly locked my front diff and and installed manual hubs so i didnt have to worry about all the crap for the ADD its one big PITA!!!! i can show you links for that. http://www.4x4wire.com/toyota/tech/add/ here is a link to the ADD i hope that can help you out

fireman1559

http://www.off-road.com/trucks4x4/ar....jsp?id=399612 here is another one for the ADD system i wish i could help you out more

cbohannan1985

Can you tell me what I need to get and do besides hubs to switch to manual hubs

fireman1559

really all you would need to do is get something like a hose clamp or CVboot clamp to lock the diff in place. and something to cap off the vaccum ports on the actuator and white lithum grease and some wheel bearing grease and of course diff fluid. it shouldnt take you to long to do this once you have everything to do this

cbohannan1985

cool thanks

904_runner

just screw with the vacuum lines..

I had the same problem because thsoe vsv's for the add went out.. i ended up taking a vacuum line off one of those vsv's and hooking it directly to that 3-prong vaccuum port on the side of the plenum. That applied constant vacuum to the shift fork and kept it locked in.. Then i put manual hubs on and it was basiclaly like not having the vsv's anymore..

ANother option is to convert the front diff to a non add style, and complete remove the shift forks and add sytems. This will also require manual hubs.

fireman1559

if you remove the shift fork when you convert it to non ADD wont that not work cause dont you have to lock the shift fork in to the locked postion?

904_runner

What i meant by that is getting the solid axle tube off of a pickup/4runner without add...

So you unbolt that whole piece and put it to your front diff. That way you completely removed the whole add system...

cbohannan1985

would the eletical part of the diff box couse the same thing and what is the name of the switch in the diff box cuz im not even getting the 4x4 light on the dash

904_runner

Can you explain the diff box??

Are you saying that wire that comes out of the vacuum modulator? that is for the 4wd light.. That will light up when the front end is engaged..

I would check all the vacuum lines for the system.. if not it might be the vsv's..

fireman1559

ahhhh ok i get ya thats another option

fireman1559

i second that

cbohannan1985

ok cool thanks guys