thechief86

Well, after a month long stint of replacing parts on this truck like crazy, I finally got it running halfway decent and started daily driving it. For the last month or so, I've driven it to work, about a 60 mile round trip, 6 days a week, with no problems, and had driven it about 200 miles each way to see my grandad one weekend.
This past weekend, I drove it back to see my grandad, and happened to go offroad a little bit (nothing serious, just a logging trail with a few mudholes), and used 4lo most of the time to just creep around.
Everything seemed fine, and I drove another 40 miles or so around town with no issues, so I went through a car wash and started the 200 mile trip back home.
About 45 minutes into the trip, the car just DOVE left like the left caliper had locked up, and it got a strong vibration that felt similar to a warped rotor.
So I pulled over, and couldn't find anything wrong, no excess heat around the hub, and the brakes weren't even warm. No obvious problem with the steering, suspension, or cv axles, so I took off again.
5 minutes later, the truck takes another hard dive, no wierd noise, just a noticeable vibration, and the thing wants to go left.
Now I'm trying to just drive to an exit and see if I can see something with more light, and it's trying to dive randomly every 3-7 seconds. Once I got there, everything still looks fine, nothing is warm indicating excessive friction, and the only thing I could find was that the front driveshaft doss not spin freely in 2wd, which makes me think I'm stuck in 4wd?
The light went off, and the shifter moved fine, but I guess the ADD didn't disengage.
I looked under the hood and everywhere I could see on the front end, and all the vacuum hoses look good, and are still soft and flexible.

I turned the flashers on so people would have some idea to stay away, and I was pretty sure I'd get pulled over for looking like a drunk.

Anyway, I never could figure out what was going on, as everything looks and feels fine in the front end, and just drove on home, fighting a hard left dive every few seconds and cussing a lot.
I have some manual hubs I can rebuild and use, but I need to figure something out in the meantime to get back and forth to work.

91 4runner, 3vze, 5 speed, 4x4, stock on brand new 32" bfg Mall-terrains
Any suggestions?
It's never mattered if a front axle disconnect system didn't disengage on any jeep or chevy or dodge in the past, sometimes they just didn't work in 4x4, but 2wd was fine...

wyoming9

iTrader: (1)

Get the front of the truck up in the air and figure out just what is wrong.

Now my 4Runner is parked in a mix of mud and snow that is my driveway.

I would check this myself

I am not at me best after a long day at the welder mines





At any time did you feel the front differential was that hot .

It is not trying to kill you yet give it time.

kcaudill

do you have your axles looked into 4wd? Could be a CV is about to explode. turning freely then hits a bad spot in the cv and binds up, causing the truck to pull left

thechief86

CV's are new, and best I could tell nothing was getting hot.
I haven't installed manual hubs yet.
-
-just now jacked it up and spun the wheels. The front driveshaft spins, and the wheels have no binding issues. Why is this different than just driving with manual hubs locked in 2wd?
Front shaft spins all the time on my jeep with no issues in 240k miles...
Anyway, now I know that the problem lies with my vacuum disconnect system, so I'll park this pile of crap until I get a dry day to install my manual hubs.
I wish they had just left well enough alone and kept manual hubs on everything to start with.

wyoming9

iTrader: (1)

Like anything new it seems hard to understand once you learn your way around it is quite simple.

Remember there is a market share out there that getting out and locking hubs just is not done it is not proper .

One could break a nail meaning a emergency trip to the Nail Salon at triple the normal rate.

RJR

Installing manual hubs and putting them in the unlocked position will hide the problem you are seeing, but it won't make it go away. You still need to get the ADD (automatic differential disconnect) working properly, or defeat it properly, or you won't have 4WD when you want/need it.

The ADD has a number of parts, but conceptually it's simple. A switch in the transfer case closes when you select 4WD. That closes a relay which switches a couple of vacuum solenoids on the front passenger side fender under the hood. The vacuum lines go to the front diff and activate the ADD collar to lock the driver's side drive shaft to the differential. To troubleshoot:

- With engine off, ignition on, move the transfer case back and forth between 2wd and 4wd. You should hear the relay click under the dash. If you don't, you have a relay or transfer case switch problem.
- If the relay clicks, raise the hood and listen on the passenger side as someone moves the transfer case lever. You should hear the vacuum solenoids clicking on the fender.
- If those work, start the engine and pull the output vacuum lines (the ones that go to the diff) off the vacuum solenoids. Put your fingers over the open vacuum solenoid ports, have someone move the t-case lever, and note that the vacuum changes from one port to the other.
- Finally, trace out the vacuum hoses to the differential and make sure they are healthy and connected.

One last thing. It's likely that you have other problems. If the ADD doesn't disconnect, it should not cause jerking to the side. You should still have smooth operation. I would be concerned you have a bearing problem in your front wheel.

thechief86

Thanks, RJR, thats actually more information than i previously had in the way of troubleshooting the ADD.

I am aware of all the parts of the ADD system, and it had been working flawlessly the entire time I've had the truck, including some light wheeling and commuting in the snow, but it always disconnected when put back in 2wd. I have been stranded by unreliable vacuum operated 4x4 systems in the past, and I use 4x4 more than the average person. So before I even had a failure, I did some research on how to defeat the ADD system and also clean up the extra mess of vacuum lines I will no longer need once I convert to manual hubs. This simply sped up the time I was going to go ahead and do all this.
I'm thinking at this point that I can go on and install the new hubs and defeat the ADD, and then drive it to see if I can figure out the wierd jerk issue, or if it just goes away.
In the meantime, I'll rely on my motorcycle and my noisy jeep.

thechief86

Manual hubs and ADD defeat solved my problem, with no issues in 2wd or 4wd, as long as hubs are unlocked on dry pavement.
I can already tell that there is less drag and that my fuel mileage has gotten better, so either way, I like this modification already.
I haven't found any problems yet with the front diff, driveshaft, or cv axles, or wheel bearings, so I'm kind of stumped on why it drove wierd in the first place, aside from knowing that the axle disconnect fork was not sliding back in 2wd.

Oh well, I'm not going to stress about it as long as everything is working when I need it to.
Next project will be to get rid of all the ADD solenoids and vacuum lines and plug the stuff that needs to be plugged, and figure out my code 21 issue for the O2 sensor.

Thanks for the replies, if you guys have any more suggestions, I'm all ears.