Unique 4 wheel drive issue

I know there are a millions threads on the 4 wheel drive issues and lights blinking. Mine is different I promise. I have an 06, manual, 6 speed. I'm familiar with the truck and the all the 4 wheel drive stuff. I've fixed the front actuator a couple years ago and has been flawless since then. It always goes into 4 wheel hi, in like 5 seconds or less. I stop put it in 4 lo. You here the click in the glovebox, the clunk come from the transfer case, and the truck is in 4lo. It will pull its self up anything with little to no gas. The funny thing is the 4LO light does not stop blinking. There is no beeping, and you can drive like this, and it most definitely is in 4 low. I know it's not a huge deal, but my diff lock will not engage as the truck does not think it's fully into low range. If you stop and trun the knob back to 4hi, the clunk in the transfer case happens, the click in the glove box and the light stops blinking and its back in 4hi

Is it one of the position sensors in the transfer case? I know this is a pretty technical question. I did try tapping it with a boxed end wrench today on the trial but it was hard to hit it well. Does anyone know if you can buy just the position sensors? I had a similar issue when I first picked up the truck with the 4hi, and taking the position sensor out and cleaning it has seemed to make it work every time since then.

Any help is appreciated.

Also, definitely not something I am very concerned about as I only really use my diff-lock very infrequently, but if I engage it in low range, you can hear the rear end lock up with a clunk and the wheels chirp and it in engaged. I have even verified by jacking the truck up and seeing that the two wheels are locked together. But, the diff light also stays blinking. Turn the switch off the diff unlocks and light is off. When I first bought the truck I had to put a new used locker motor in it because the original owner just never used it and the motor was so rotten. I have pulled the position plunger out of the diff before and pressed the ball with my finger and the light will stay solid. Does anyone think that when I installed the new motor that I got it like 1 tooth off and it does not move the rack enough to engage the light?
Just looking for some advice, old truck stuff here.

 

Not in 4 low unless you stop, put tranny in neutral, then switch to 4 low.

You didn't mention anything about neutral before switching to 4 low, so not sure if you're doing that.

Oh wait, manual trans, never mind. I'll just go back to drinking my beer. I'm not sure how it works with a manual on these newfangled models that don't have a 2nd shifter.

 

Yeah you have to have the clutch mashed to the floor, and it is absolutely in low range, wheels bind up a little when turning, truck idles at about 1 mph.

 

You need to check your limit switch voltages and see which one is out of range in 4 low, it's very possibly you have the actuator a tooth off.
https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

Might be a silly question... but are you sure there isn't a 2-low module installed?

 

Thank you, I wish I could have found this a long time ago. I will also clean that ground, and probe around with my multi-meter.

 

Let us know what you find

 

Well, I just went out and probed around. This time when I put the truck in 4LO it just clunked right in and the light stayed solid. I cycled it about 10 more times and the same result every time. It's been about 4 hours since I drove the truck last. This seems to be something that starts to happen after driving for a little while regardless of 4-wheel drive or not. What would cause a signal change for the low range with heat or drive time? That ground on the back of the motor?

 

I wouldn't think so as it feeds all the limit switches, if it had a problem I would expect there to be issues in all 4wd modes not just low.
I'm thinking either a bad limit switch, LO switch, or your actuator is 1 tooth off and not quite clicking the LO switch in.
Really need to see which limit switch is out of range when the problem occurs to troubleshoot further.

 

If you don't use the diff lock regularly it may not engage. My Tacoma was my everyday driver for the 1st 9 years I owned it and I made a habit of engaging 4X4 hi, low, and locking the rear diff occasionally. But my wife drove it as her primary vehicle for about 2 years before I got it back. I never had any issues getting into 4X4 high or low, but it simply would not engage the diff lock at first.

During turkey season a couple of years ago I drove it on a dirt road 3-4 times a week for about a month. This was just as the Covid shutdown started so I had nothing else to do but hunt several days a week. I was certainly social distancing. I kept trying to engage the diff lock every day. For about 2 weeks it simply wouldn't engage. But finally, one day it did. And has worked perfectly ever since.

 

Yea non use and/or the vent hoses on the actuators splitting cause the majority of 4wd issues.

 

Yeah, like I said I know it does engage, I'm almost certain that the rack that gets pushed by the motor is just one tooth off for the locker motor.

 

I put the multi-meter in the center console so next time I go for a longer drive I will try to put it into low. If it still flashes I will test those plugs.

 

It has been doing this for a while now, and It will go into low every time if you try first thing when you get into the truck, but maybe after you drive to a trail head or around for a day and then go to use 4 low, it will engage low range but the light continues to blink.

 

You will also need something to backprobe the connectors, don't try to shove meter leads in them.

 

Consider cleaning your electrical contacts. Connectors are the scourge of the earth.

 

I'll second the other reply about turning on the locker now and again..it really helped my 1st Gen with when I really needed it.

 

My guess is likely the 4lo detent switch, the seal breaks down and oil gets between the ball sensor and housing which insulates the ground connection intermittently.

 

Sort of my guess too. Maybe the oil from the transfer case gets thrown around while driving and after it sits for a little bit the oil drains back down and it will go back into 4 low. Do you know if you can buy just the detent switch? A quick search yielded nothing. I have not had another chance to go out and try to get it to do the problem again as I've been driving my work car.

 

Yes you can. It’s about a $40 part if i recall. You can also pull the old one out and test first. Only takes about 5 minutes to do.