2012 MT stuck in 4low

Hey so there are some old threads about this issue on 08 tacos, but my truck will NOT come out of 4 low. I've tried backing up, forward, shaking steering wheel while moving, standing on the clutch. Nothing is working. I am currently letting it sit and run with the switch in H2 to see if it fixes itself. 4low light is blinking and beeping at me, my tracoff and traction control off light are illuminated as well... Please help ASAP. I Can't remember the last time I put it in 4low if ever, I have been deployed so the truck sat for awhile, but I have been driving it fine for almost a month. I have just never put it in 4wd. Thanks for the help guys and gals

 

So, after a long time of sitting at idle, going forward and reverse I parked the truck for 15 min in H2 position and when I put the key to the "on" position the actuator popped it into 2wd. Very loud clunk, sounded very rough. But she's fixed. All lights went away as well.

 

Right.
Those lights *always* come on when in 4L. That part is perfectly normal and nothing to worry about.
The blinking light means that it is in a state inconsistent with the setting.

4L can be a little bit weird to work with. I don't think that there is actually anything wrong with yours, you probably just had wrong input conditions to make the shift.

With a manual transmission (like yours), the shift from 4L is done like this;
1) Dead stop. (I believe that the automatic can be rolling slowly, but the manual MUST be DEAD STOP).
2) Clutch in ALL the way.
3) Transmission in NEUTRAL position.
4) Rotate the knob from 4L to 4H position, and give it a moment to make that shift. DO NOT jump straight to 2H, that will freak it out.

If you turn the knob and it blinks and nothing happens, turn it back, and then try again.
Messing with the steering has no impact on the shift between 4L and 4H in either direction. The steering move is for the front differential disconnect, which impacts the shift between 2H and 4H only. Similarly, driving it around to "loosen" driveline binding won't help either, since that only relates to the transfer case front output shaft.

The 4L gear is via planetary gear connected to the transfer case input shaft. LOW is through the planetary gear, HIGH is connection straight through.

There is a very slight possibility that the straight-through gears won't align, in which case you reset the transfer case to starting position, stick it in 1st or R, and roll it a couple of inches, then repeat the process.

Remember though, that you must ONLY shift the transfer case ONE position at a time.

The "clunk" when shifting from 4H to 2H is not unusual. Nothing to worry about. Just means that there was some tension on the driveline when it released.

 

You must be under 3mph to shift to 4 low on both the auto and manual. Auto must be in neutral, manual can be in gear (i think) but you must have that clutch pushed ALLLLLLLLLL the way to the floor.

I find its easier to get in and out of 4low with just a slight roll.

 

Manual must be dead stop. No rolling.
While it *can* be in gear, having it out of gear ensures that there is no pressure on the input shaft, which makes it easier.

 

Thanks for the inputs, I tried all of this that you guys mentioned last night for over an hour, but it randomly just fixed itself after I shut off the truck for 15 min and as soon as I put the key to the "on" position it pulled out of 4low and straight into H2. The very first time I went to take it out and discovered the problem I was at a dead stop in neutral, just can't remember if I had the clutch in or not.

 

Also it should be mentioned that your manual states to drive 10 miles a month in 4WD to keep it lubed and fresh. Not doing this can make it more difficult going between 2H, 4H, and 4L. If you only use it when you need it, it's going to fail when you need it.

I kick mine into 4H about once a week for a minute or so whenever I'm on a long straight stretch of road going 45 or so mph. I come to a stop and then run through the gears in 4L less often, maybe very month or two either in a parking lot or when there's nobody behind me on a residential street.

 

Yeah this is what im assuming was my problem, being deployed my truck say for a long time so 4wd wasnt used for a long time. I found out doing research last night the manual says that, it's definitely going to be something I do more often, it was a scary thing to have happen.

 

That 10 miles a month is complete and utter nonsense.

 

Did your extensive scientific experimentation determine that only 9 miles a month is necessary?

 

ZERO is adequate. Use 4 when you need it, not when you don't. Just test it occasionally to make sure it works so you aren't surprised when you need it and it doesn't.

There is nothing IN it that needs to be engaged to be lubricated.

 

While it's true that it's the engagement action that you need to work more than anything, you're a fool for coming on here and insisting the 4WD system should get zero miles put on it during long periods of disuse. I shouldn't be surprised, you seem to be the type who likes to make controversial statements to start arguments so you can show strangers online how smart you are.

But since I don't want people here to get bad info...

The chain, CV axles, front diff, front driveshaft, and all associated bearings should be worked under load with some regularity. Like any mechanical device that you need to be reliable you significantly decrease your chances of a failure during times of need if you use the system under similar load (driving while engaged) regularly during times of non need (link to an example I made earlier). Straight lines only on pavement of course.

The 10 mile thing is a rough recommendation and I said myself I only do about 3 miles a month, spread over 4 engagements. A few times a year is probably fine. I do it enough to give myself piece of mind.

 

Go ahead and put a camera under your truck and WATCH what happens during normal operation in 2H.
Those parts still move. They aren't just sitting stationary.

 

Front driveshaft doesn't move in 2hi. Ring and pinion also don't move in 2hi. Neither does the front output of the transfercase. The cv shafts and the spider gears inside the front diff are the only parts associated with 4wd that move in 2hi

 

Like I said, put a camera under it. It'll move. The oil in the transfer case has a high enough viscosity to pull everything along a bit, even if the gear is disengaged.
Unless you have some magical zero friction oil and bearing in yours.

 

Movement due to non-negligible lubricant friction and movement due to application of load are two completely different things.

 

@tgear.shead can I see your video please?

 

No. The purpose is to keep everything coated with oil, and for this purpose, movement is movement.

 

I am fairly certain the engineers want the 4wheel engagement for the purpose of working the actuators.

My 05 was stuck in 4lo due to the actuator.

 

Running the actuators more isn't going to fix them if they're broken. All it will do is TEST that they are actually working.