Stange 4WD disengagement

So today for the very first time I had reason to use 4wd on my Tacoma. I had to pull a semi truck out of the yard because he got high centered with his drive tires. I put it in 4-lo because the truck and trailer weigh about 60k and I was on grass. Pulled the truck just fine, got it moving but when I tried to take the truck back to 2wd it just kept beeping and flashing the "low" light. It took 10 minutes of pulling up, backing up, stopping, putting the truck in neutral before it finally shifted. However that wasn't the end of it, something in the front end made a very loud pop with a shudder through the whole truck like there was something binding as I was backing it back into the hangar, probably 150' from where I finally got it to shift from 4-lo to 4-hi and finally 2wd.

Is this normal or simply a symptom of having a 4wd truck for 4 years and never turning the knob?

 

Well...for starters, the 4wd components need to be used every so often to insure that they will work properly when you need them. 4 years is a long time to go without ever putting it 4wd. Toyota recommends 10 miles (?) a month, while that's not necessarily the magic number...the idea behind it is important.

I'm not sure that's what caused your issue but I'd be willing to bet it's related. Sounds like there was some major binding up going on from the components not having been used for so long. Have you tried engaging/disengaging 4wd again since the incident? If it does what you described again, keep it in 2wd if you can and take it to a mechanic to get looked at. That's what I'd do anyway. Good luck, hope it's nothing serious! Try and put it in 4wd from time to time from here on out to make sure everything stays working properly

 

Thank you @eon_blue I kind of figured that may be the case. I'm putting a leveling package on it along with new wheels and tires, an alignment and transmission service since I'm getting close to 60k miles so I'm going to have them look it over as well.

My next one will be a 2wd since it's obvious I have no need for 4wd and I have a Super-Duty for when I really need 4wd.

And no, I didn't get a chance to try it again, have a flight out of the country in a couple hours so it'll be next weekend before it's driven again.

 

I use 4wd and 4 low frequently. As long as you are rolling, the truck should go in and out of 4hi with very little noise. If you are stopped when switching from 2 to 4 or back, you will get that pop. It is a chain driven system, so it's like shifting gears on a bike while not moving and then trying to pedal.

As far as the trouble getting in and out of 4 low... I use mine several times a week and I frequently have the same experience you had.

 

Getting into or out of 4lo can at times be challenging in any 4X4 I've ever owned. The more stress you put on the drive train it seems to take longer to get it out. Putting it in reverse and backing up several feet helps and sometimes you may need several tries. I had to pull an F250 with a livestock trailer and some cattle in it up a steep hill a couple of months ago. It took several tries and backing up to get the gears unwound. I was probably pulling 12,000 lbs, I wouldn't have attempted what you did with a Tacoma.

Shifting into 4X4 hi and 4X4 lo for a few miles every month or so sure helps make sure things work when you need them. That is why I had to pull the truck and trailer up the hill. His truck wouldn't shift into 4X4 and he couldn't get enough traction in 4X2 to pull the trailer up a steep gravel covered hill.

 

Well it sounds worse than it was and I needed the jackass out of the way, he had our hangar door blocked. The semi has 4 drive tires (actually 8 but 4 positions) and they can lock the front differential to the rear but not side to side, He had one tire on the front drive axle and the opposite on the rear on a hump causing the other two to spin freely. Basically he just needed a little boost to get traction and drive himself out. I put the Taco in 4-lo pulled up tight on the chain and barely had to throttle it to get him moving. I was off in the grass but he was on hard gravel with the truck and of course the trailer was on the concrete in front of our hangar door. Had he been truly stuck he would have been calling a heavy wrecker while I stood there yelling after I told him to try it in the first place.

No matter now I have to find an excuse once a month to drive off-road and use the 4wd to keep everything working properly or just trade it in on a 2wd.

 

4 low, especially with them being electronic instead of manual, can be finicky at times. Typically you need to move the truck just the slightest bit, or turn the wheels to get it to engage/disengage. If you exercise the system more often it will become easier to get it in. The more you engage it the better it stays in usable condition. The clunk you felt is pretty normal. I feel it in mine often.

 

I use my 4x4 fairly frequently and sometimes get the clunk you're having. Just sometimes things get in a bind due to driving, terrain, differences in tire sizes (not saying they're different tires at all, but there will be a difference). Even when new, there is some amount of slop all through the drivetrain, backlash on the ring gears, the chain, slop in the driveshafts. When you shift out and the clunk happens, its all of that tension releasing.

I'm not a fan of the electronic transfer case, I wish it were manual shift just for reasons like this.

 

I've never had a problem putting a legacy 4x4 in low range, stop and move shift lever. The Tacoma dial is a step backwards in some ways. I exercise mine every week going in a straight line on pavement (there are no dirt roads within 20-30 miles of where I live). My 4wd engages when I want it with regular exercise.

I also get the clunk from the front axle when shifting out of low range.

 

Could just be the result of 50k over the trucks tow capacity...

 

Take your foot off the gas pedal before turning the knob to shift back into 2wd to take the load off the driveline... you won't get the clunk.

 

Well Toyota set the bar with this -


That was 283,000# over the rated towing capacity (31.44 times rated)

I was only 53,500# over the rated towing capacity (8.23 times rated)

So Toyota set the bar, I was 23.21 times lower than the bar they set so I seriously doubt the 4'-5' I pulled in low barely off idle had anything to do with the 4WD not wanting to disengage. But what do I know

 

A Tacoma could pull a train for a short period of time. Don't get your panties in a wad. Flat towing takes miniscule amounts of power vs going up and down hills for long periods of time

 

I've pulled a loaded semi a couple years ago. It was on a flat driveway and it pulled it easily. The guy couldn't get it to turn over so I got him moving and he started right up. The driver couldn't believe a Tacoma could do it. No problems with 4wd lo either when I was done thankfully.

 

I attempt this as I turn out of my driveway onto pavement. Sometimes it works, other times it seems like the 4WD deliberately waits until I am back on the throttle before it disengages with a clunk.

 

If it was on air ride which I'm sure it was, I would have dumped my suspension to get off the hump.

 

Tried that, tried pumping the brakes to get power to the other tires and nothing worked because the steer axle was in a small rut. I moved him all of 1' then he got traction and was able to pull up.

 

Pumping the brakes won't do anything on a semi, diff is either locked or not, and it's not gonna send power to the non slipping side. But good to know my taco could pull my semi for future reference! Lol!

 

Well sometimes if wheels are freewheeling and you apply some brake it "can" put enough drag on those spinning to put a little power to the ones stopped. And in this case it did and would move just an inch or two but the steer axle was in a small dip and just wasn't enough to get it moving. It's a long shot that it would work but pushing a brake pedal is easier and faster than getting the Taco and a chain.

 

You could have manually adjusted up the slacks on the brakes with the spinning wheels so the brakes were tight, and backed them off the proper adjustment afterward.

But I too have pulled a loaded truck and trailer with my tacoma that had melted about 3" into the ice in the yard over the weekend. I was on ice / compact snow, and the back of the trailer also needed some help from the bobcat at the yard to get it out. I probably could have done it alone if I'd thrown the tire chains on the taco. Not bad for 105,000 lbs.