94 4wd 4runner 3.0 5speed - auto hubs.
Need a little help in starting to solve this problem, I'm not getting any 4wd.
No dash lights, no hopping/bucking on pavement (H4 or L4) I do hear a switch click under the dash when moving to and from H2wd-H4wd. But thats about it.
Where would I start?
tk

 

VSV for 4wd

 

This might help

http://toyota.off-road.com/toyota/ar....jsp?id=399612

 

Sounds like the actuator or the vacuum lines leading to it. I would start with the silenoids and work your way down from there looking for any leaks. You might try taking off the vacuum line on the passenger side of the selenoid and see if there is any suction when the truck is shifted into 4 wheel drive.

 

Found a loose hose coming from the bottom of the little canister looking thing on the firewall side of the VSV assembly. Can't see anything obvious it could attach to. It's not sucking or blowing either in 2WD or 4WD.
Here's a pic

 

There is also another canister just on the other side of that fender up in the wheel well. I think you might have to remove the plastic wheel well thingy to see it and make sure that has both vacuum lines running to it.

 

I have a 1993 SR5 p/u with the same configuration and with the same problem. Would your help to tktmsa apply to me also?

 

While following some vac lines I found an interesting issue: Do you think 1/2 inch hole in the front differential would be causing some problems?
tk

 

That piece you circled is your VSV for the ADD system.

And define a 1/2" hole....where is said hole?

 

Lovely hole is in the front carrier cover, low. How hard is finding that part going to be?