mroe

I have a 1995 Tacoma 6 cyl 4x4. It doesn't have locking hubs, but just a lever on the floor that switches between 2xH 4XH & 4XL When I was tring to pull a boat out of the water and it was slippery, I put it in 4x4H (even tried 4x4L) there use to be little light that came on to tell me I was in 4x4, but they don't come on now, and it obviously was not working since only the rear wheels spun around and not the front. What could be wrong? Hopfully it's something I can fix, Any suggestions?

jeremys73

you may have to drive in reverse a bit to get it in 4wd, not a good idea on a boat ramp though

mroe

The handle does move to the positions, but the 4x4 does not work. Could it be maybe some type linkage adjustment?

Roadtripr

If you have the same system as the 4runners then it might be a vacuum leak. There are lots of post on it that will explain it.

https://www.yotatech.com/search.php?searchid=1422802

here is one quote from Midiwall:
Just so ya' know, the light on the dash is a true telling of the state of the front end. It's wired to a switch in the front housing that gets hit when the collar slides into place. The point being that unless the lamp is burned out, you can trust that it's not just an idiot light.


The locker is driven by vacuum, the solenoids are on the fender wall on the driver's side, the vacuum reserve tank is up under the fender on the driver's side, outside of the engine compartment.

Tracing the hoses amongst the solenoids will be the first step. Look for a vacuum leak in there. Also check the hoses leading to/from the storage tank.

With a helper's finger on the 4WD button in the cab, you should be able to hear the solenoids engage under the hood. There are two, and they work together to manage the vacuum at the locker. You can leave the engine off during this part to make it easier to hear.

If you can't hear them clicking (using a long screwdriver with the tip on the solenoid and the handle in your ear will help) then you're looking at an electrical problem. Check the wiring, connectors, fuse...

If you hear them clicking, then start the engine and move to pulling the hoses off to be sure that the vacuum's being routed. Put your finger over the end of the hose or solenoid and you'll be able to feel it.

If there's vacuum there, then move to under the truck and be sure you have vacuum at the housing. The lines are easy to find, though you'll have to pull the skidplate.

If there's vacuum at the housing, then it's probably the acuator itself. I'm pretty sure that it can be replaced from the outside. I remember looking at it when I had similar problems with mine.

mroe

Here's what's weird. I got it home, crawled under it. I could turn the front drive shaft by hand. I shift it into 4x4, then I can not turn it by hand. It seems the 4x4 light sometimes works and somethings don't Are you sure it could be a vacuum line? I don't think it's a vacuum shift, it's direct linkage. Where would the vacuum shift or mechenisum be?

mike_d

it's not that it's vacuum shift, but the ADD system is vacuum actuated. you'll have a direct connection between the driveshaft and the tcase, but the front diff (passenger side, i think) is connected to the front wheel via a vaccum actuate splined thing. it's described much better in other articles that. based on the age of your truck, i'm pretty sure you have ADD. if you search you'll find some good posts that explain how it works.

edit: here's some good info on ADD: http://www.off-road.com/toyota/tech/add/

mroe

I looked all over and I don't see that I have ADD. No Solenoids on the engine wall or an actuatore on the front diferencial. So mine must be some type of manual shift. Bought a Chilton's manual, even thta doen'st help. Show how to take everything apart, but no adjusments to trouble shooting. Kind of a crappy book. Any other suggestions? Something moust lock thge front drive shaft to the trasnfer case.

mroe

OOPS! Guess you were right. I took the skid plate off the bottom, to get a better look. Guess I do have ADD. Traced it up to the top, where I found a vacuum line off. Everything works fine now. Thanks to everyone for the responces. Saved me a trip to the dealer and probably a big service charge to just put a vacuum line back on. Thanks again.