EODGibby

Hey everyone, just made this account for a friend who's having a problem with his truck. I'm not too savy with Toyota's so I figured I'd post in here for where to start looking for his problem. I'd do a search, but we're at work and I don't have much time to be browsing around. I'm hoping that by posting this now, we'll have something to work with by the end of the work day. He's not an offroader, but the roads are crappy with snow and he'd like his 4wd back.

The truck is a 1986 Toyota 4x4 P/U (Tacoma?), V6, auto tranny, not sure what type of transfer case comes in these. Basically, his transfer case won't go into 4hi or 4 low. The lever will physically shift into the positions, but there is no 4wd. The indicator light on the dash will click and flash three or four times when going into 4hi, but then stays off. It almost seems to me like maybe a switch or solenoid has gone bad?

One other note. By reading the 4wd instructions on the visor, it seems like this truck came with manual hubs. There are just normal caps over the front hubs, so I'm assuming that they were changed to automatic hubs at some point?

Anyone give me an idea of where to look? I'm going to go check fuses and crap at lunch but beyond that, I'll need some help. Let me know if you need any more info about the truck. Thanks in advance.

muddbogg21

If you go under your truck i want to say since its a automatic there is a lever that actually is connected from your shifter to your tranfers case it could of came disconnected thats what happened to my buddys auto 93 4runner. just go underneath find your tranfers case shifter and follow where the lever goes you should be able to tell if its connected or not start there

EODGibby

Ok, so I posted before and got deleted because this is apparently a common problem. So I did some searches that pointed me in the right direction and was able to get a little further in figuring out what is wrong. Now I'm stuck and need some specific guidance that I haven't been able to find in searches.

NOTE: I originally posted that the truck is an 86 but my friend corrected me that it is a 92 (this is his truck). It won't go into 4wd. The switches in the dash appear to work as the 4wd light flashes on and off and clicks. I THINK it is a vacuum problem. So here's what I know...if you guys could help me out here, I'd appreciate it.

Bear with me because I am not familiar with part names for this system. On the passenger side of the engine compartment above the wheel well, there is a vacuum distribution point. It is a plastic bracket with a blue one way valve, a bigger blue valve of some sort with an electrical plug on it, and a nearly identical red valve with an electrical plug on it.

The one way valve seems to supply vacuum to the other two vavles. It seems to be working fine. The other two vavles have a vacuum input and (I'm assuming) output. Both have vacuum going into them on the top nozzle. With everything attached as it should be, the diff will not go into 4wd (the drive shaft is spinning). Detaching the various vacuum hoses does nothing to help. HOWEVER, if I detach the hose from the lower nozzle of the bigger blue vavle and then start the truck and shift it into 4wd, the 4wd will work.

I'm assuming (from my searches and reading) that this is because the truck uses vacuum to keep the sleeve pulled away from the diff and to keep the truck in 2wd.

So with all this info, I'm hoping this thread doesn't get deleted and I can get a little help here. I'd take a picture of what I'm talking about, but I'm at work and not allowed to put pictures onto the computer. So does this problem lie in one of these valves or do I need to be looking elsewhere? Any and all advice is appreciated. Thanks.

waskillywabbit

iTrader: (-1)

www.ncttora.com/fsm

EODGibby

Guess my post got moved again. Doesn't make sense to me, but whatever.

Thanks for the link waskillywabbit ...is the FSM for the 4runner the same for the pickups? I only saw a 4runner FSM for the 90-95 years.

4Crawler

iTrader: (3)

http://www.off-road.com/toyota/tech/add

waskillywabbit

iTrader: (-1)

https://www.yotatech.com/forums/f104.../#post51319435

https://www.yotatech.com/forums/f121...thread-202382/

ADD is all the same on those year models. Please read the above links.

Glad to help but all the information you seek is readily found with some work on your part by searching and reading. Expecting us to help when you don't even know what truck you are working on to start out with is a bit much.

I moved your threads and merged them instead of just deleting them as is the typical protocol.

DeathCougar

iTrader: (23)

If the 4wd light stays on solid, the truck is in 4WD.

Check the vacuum lines to make sure there is vacuum at the solenoids, and again at the diff. If not, you have a problem.

Check out the links provided above.

And next time, just search. Telling us you don't have time to search, then spending all day posting new threads and long replys doesn't add up. You could have solved the problem already just by checking in the FSM under the ADD section.

Tofer

Did he lock the hubs?

DeathCougar

iTrader: (23)

There were no hubs to lock, as he has the ADD system, based on the OP's initial, if somewhat incorrect, info.

Btw, just because a vehicle has a sticker for instructions on locking in the manual hubs doesn't mean it ever had them. Toyota put generic information throughout the truck regarding how to shift it, and things of that nature. I bet if you open the owners manual, it has operating instructions for a radio the truck probably never had too

EODGibby

Actually, after my first post, I did spend about an hour searching and reading (on my lunch hour). It put me in the right direction. Normally, I am good about searching first and asking later but I was at work and didn't have time. The truck belongs to a friend and he gave me the wrong year initially. He isn't too mechanically inclined...

I don't mean to be rude, but I was kinda getting pissed off at first. So sorry for that. The truck is a 92 (I verified) V6, auto, with ADD. No manual hubs. The 4wd light flickers/clicks on 2-4 times, but does not stay on. So here's what I've done:

-I did an ohm test on the two ADD solenoids but wasn't quite sure how to do the flow check since I can't really hear the vacuum with the truck running. The ohm test was good for both.

-I pulled the ADD indicator switch and did the continuity tests. It checked out per the FSM.

-I couldn't locate the ADD relay, transfer pressure switch, transfer position switch, or transfer indicator switch (crappy FSM picture). Looking at the picture again, I think I had a duh moment and these may actually be on the transfer case. The picture makes them look like they're in the engine compartment. If anyone can verify, I'd appreciate it.

My friend had to go run some errands so I don't have access to the truck again until tomorrow. I'm going back to read the links you guys supplied. But I did do a search after my initial post which is why I reposted with more specific info the second time. I really do appreciate your help. Thanks.

DeathCougar

iTrader: (23)

Now we're cooking with oil!

Easy way to check the vacuum lines is wihh the truck actually running. You should feel suction on the hose going TO the ADD solenoids (aka Vacuum switching valves, mounted on the pass side, one blue one red)

EODGibby

Did some more reading last night and have a few more things to try on my lunch.

EODGibby

Well...after troubleshooting nearly the entire ADD system, I figured it out. I'm kind of embarrased to say it, but the vacuum lines were switched. That was the one of the first things I checked yesterday, but I must have done something wrong when I checked it the first time. After finding all the system components in working condition (except the ADD Relay...never did test it) and ensuring that I had vacuum at the ADD actuator, I tried applying manual vacuum (by sucking on the lines). At first it didn't work and I just collapsed the hose, but then I felt the actuator slide over and lock the 4wd in. I'm thinking it may have been jammed up a bit. It was much easier to actuate after the inital try. The vacuum lines look nearly new, so I'm guessing the previous owner tried to fix the system and put the new lines in backwards.

So thanks for the help and thanks for the link to the FSM and link to the explanation of the ADD system. Turns out, my mechanically challenged friend never had 4wd at all (he thought he did). He's only owned the truck for a short while and it is his first 4wd vehicle.

4Crawler

iTrader: (3)

That is the most common problem from what I have seen. Shop woks on truck, pulls vacuum lines, then hooks them back up (w/ 50% chance of doing it wrong unless they labeled the lines prior to removal) and while the engine runs fine, they never see if 4WD works.

DeathCougar

iTrader: (23)

Ran into this exact problem yesterday with a customers 4Runner. Had the engine rebuilt by some cheapo mexican back alley shop, then his 4WD stopped working. Switched the vacuum line off his EGR valve and back into the intake, and Viola!

Glad you got her fixed up. Doesn't it feel good to do it yourself?!