4WD Disengagement Question

Frequently, when driving in 4WD High and switching back into 2WD, I feel a resistance which feels like gears touching and can hear a sound that corresponds with the vibration.

Doesn't seem like normal operation to me, but looking for feedback. Thanks!

 

How long does the sound and vibration last? The switch from 4h to 2 isn’t instant.

 

At least a few minutes/miles, sometimes until I shut the truck down, run my errands, and then get back into it.

 

Mine doesn’t do it. In snowy and icy conditions, I switch back and forth while driving because some roads are cleared and some aren’t. I just let off the gas and make sure wheels are straight before switching. I’m usually going under 20 mph too. The indicator flashes for a few seconds then stays lit.

You’re under warranty. If you can reproduce the sound, go by the dealer and ask them sometime.

 

Not normal. Once disengaged and the light on the dash turns off (shouldn’t take more than 1-3 seconds) it should be back to completely normal 2WD. Shouldn’t feel any different.

 

I do the same thing...right down to letting off the gas.

 

I let off the gas as well.... normally making my switch from 4WD > 2WD around town @30mph ish. Thank you all for the feedback

 

How many miles?

t-case ever serviced?

 

30mph seems fast for changing drive, I know the system can do it but to me that's one way to blow the transfer

 

I do the same as a precaution. Manual states to be under 62 when changing to or from 4HI, but sorry, can’t do it. I’d have thought 30 a bit much, but if the manufacturer gives 62 as a boundary then 30 seems fine to me.
Too many trucks on the road and warranties they’d be on the hook for if it was different, right? Just an opinion from someone who has only owned a truck, any truck, for about 5 months.

 

Been actuating 4hi on and off up to about 50mph for 80k miles on the second t-case and been issue free. I'd say maybe 60 activations a month, give or take a dozen.

 

25k miles on the truck, its a '19 that I purchased new...

 

On my '78 CJ, 2012 T4R trail, and '21 tundra I always creep when shifting into 4hi. No real reason to do a flying shift other than "just because the manual says I can."

 

Sometimes the driver's side front diff bearing can sound off like this. It's completely silent in 4WD and when going back to 2hi suddenly the noise + rumble that is usually ignored suddenly starts up again and it's a noticeable difference

 

I haven't heard about this yet... "normal operation" or something that needs to be addressed (and how quickly?). Thank you!

 

It's in the design. Where the driver's side axle plugs into the differential it goes through a single needle bearing and into the spider gear. How tight the needle bearing is to the axle shaft determines how well the spider gear stays aligned. When that alignment is a little off, the differential growls. Mine has always done it to a degree and it's louder in the cold weather. Every 4x4 Tundra and Tacoma have been built this way to my knowledge (and there's lots of threads on tacomaworld about it). Sometimes dealers will replace the front diff under warranty if the noise is bad enough but it may come back again.

The way to tell if this is what you're hearing is go 30-35 mph in 2WD, shift into 4HI and listen for it to get quieter. Then shift back into 2WD and listen/feel for a faint rumble coming from under the floorboard. Generally the diff is quiet under 20 mph and over 40 mph so you won't really hear it then. If you're hearing gear grinding noises and not something caused by this bearing that's something else and definitely should get it looked at.

If it's bad enough then yes, the bearing can fail, but afaik that's pretty rare. It's more likely on a lifted truck with the additional stress from the increased angle at the CV joint. Sometimes the axle shaft can wear a groove where it sits on the bearing and the clearance will open up.

I might eventually tackle mine with the ECGS bushing replacement but it's not a high priority.

 

I have switched back and forth between 2wd and 4wd at over 55 mph many times smoothly and effortlessly.

 

Id think with all the electronics, if the truck wasn’t able to switch then it wouldn’t and wait until it was able to do so.

 

I had a lot of vibration from my front axle, traced source to bad needle bearing on driver's side. Installed East Coast Gear Supply bushing, made a huge difference.

 

I took the truck in for the tech to take a test drive. I was able to replicate the issue on my drive in. The tech goes out for 5 minutes, unable to replicate of course. I took the truck back and was able to replicate again. I then returned to the dealership and scheduled a ride along.... which is the last thing I want to do during COVID, but I've never had a tech able to replicate the issue on any car I've owned. A little frustrated.

Thanks again for all the input on this forum.

 

Update... just completed the scheduled ride along w/tech. New front diff is on order and will be installed about two weeks from now.

 

The mountains in Oregon during the winter will have sections of snow/ice and then bare pavement. Some area are not maintained as well as others. If I am driving over the Cascades, I might switch between 2hi and 4hi 30 times during the trip.

 

My 2013 shifts between 2wd and 4wd fine at higher speeds, although now I'm getting a clunk when shifting in and out of 4wd. Shaft need lubing?

 

Mine would continue to flash "4HI" even after I moved the knob to 2WD.
I found that moving the knob from 4HI to 2WD and then slightly accelerating resolves this issue...Everytime.

 

Mine sometimes does the clunk and it did it even when it was new. Sometimes everything is aligned and it's very smooth and sometimes I hear the clunk. If you do it long enough you can figure out a speed and situation that doesn't clunk or does it less but that's normal. My Tacoma did it for many years with no issues.

 

Smooth as butter on mine have u seen the dealer?

 

I meant to have it looked at last on my last oil change but forgot. I think maintenance calls for lube at certain mileages no? Next time!

 

This is exactly what is happening to me. I haven't tried accelerating after returning to 2WD but I will now. Thanks!

 

My winter 4HI problems are gone after replacing stock Toyota fluid with Ravenol MTF-3. Switches back and forth like clock, in any temperature.