In and Out of 4WD "Clunk"

I'm sure this has been covered 100s of times, but I'm curious. (and not too good at searching.)
when I go in and out of 4wd while on the fly (30 mph or less) I really hear a clunk, and feel it too. With all the snow this year I am in and out of 4wd often.
In 4 high on dry pavement, the drive seems to bind up, so I go back to 2wd. On a snow covered hill I have to go back to 4wd.
SHould I come to a copmplete stop? Sometimes its not such a good idea (to stop.)
I don't want to wear out the little motor that shifts it back and forth.
Is the "clunk" supposed to happen? Should I be coasting, slowing down, etc when I shift back and forth?
Anyone know what is best way to do it?

Thx,
Jeff

 

No 4x4 on dry pavement at all, you will ruin your drivetrain

 

FWIW, I make sure my steering wheel is straight before I switch back from 4hi to 2wd. I would straighten the steering and then go back to 2wd while coasting.

 

I had a old jeep wagoneer (64) when I was younger. It was the same way. No 4wd on pavement.. My 4runner seemed ok in 4wd on the pavement. This is my 1st winter with the Tacoma.. It brought back memories of the old jeep. I need 4wd to get out the driveway. But when I hit the pavement.. I could tell things were binding up.. I have to admit, I'm a little surprised Toyota does not have a little more "flexibility" in the drive system. I don't think I've gone more than a few 100 yards on dry pavement in 4wd.. (I doubt I have hurt anything.)
I'll hope for the best with the cluncking.. What is top speed you can shift in and out of 4wd?

 

As said, don't use the 4WD on dry pavement.

That said, you don't have to be on dry pavement to get a clunk. You're getting a clunk because you're disengaging it while there is pressure on the drive line. The clunk you're hearing is that pressure coming to a sharp release.

When you disengage the 4WD, try to be driving straight and neither accelerating or decelerating. If you're accelerating, there is pressure on the drive line. If you're decelerating and getting engine braking, there is also pressure on the drive line.

 

This is weird.. I have snow covered streets everywhere.. I jump out from a side street (snow covered) on to a 60 mph highway.. I can't get moving unless I'm in 4wd. The highway is cleared.. It's easy to say "don't drive on dry pavement in 4wd." but not too realistic..
Then I'm a 60 mph with traffic.. Holding it steady.. going back to 2wd.. Oh well.. I put 250,000 on the 4Runner.. I'm hoping for the same out of the Tacoma. I would have thought they had a similar 4wd system. Obviously not.. I certainly appreciate the Tacoma has a "stronger" system.. I just wish it wasn't so unforgiving..

 

You're right, those times when you need 4WD to get off a side street covered in snow onto a cleared highway can be tough. The best you can do is wait until you're moving straight on the highway and disengage the 4WD as soon as you can before you build up too much speed. But again, you're going to get a clunk if you're accelerating while doing this.

 

You have gotten good advice so far.

I will add a little more. Vehicles designed to shift on the fly use the same axle ratios front and rear. That way there is less chance of drive line "wind up" on roads with good traction. Other vehicles use a front axle ratio that is a little faster than the rear. On loose terrain, the wheels can slip but the good thing is it is always trying to keep the front in front of you!

If you are getting a clunk, even if the drive-line is "unloaded" (coasting) be sure to check the tires. Tires that have not been rotated to keep the wear even will create a final drive differential along with binding and banging noises. You can place the truck on a flat surface and mark the bottom of the treads with a grease pencil. (vertical line at the center to ground). Roll the vehicle forward until one line goes full circle and be sure all the others match. If not, it will create "bind" when traction is good.

 

Because I put so many miles on in such a short time. I rotate tires very often.. (48k on my 09.)
I'm just going to have to hope for the best..

 

Good thread. Thanks for the information.

 

I have similar nuissance. My driveway stays snow covered for 3 - 4 months of the year while road is plowed and clean. Also need to use 4x4 to get in and out of the driveway so very often disengage 4x4 on the hard pavement. If you do that as soon as you get to hard pavement you should not get any issues.

 

I've actually even just used 4WD to get moving on the snow covered road, then disengaged before I even got to the pavement. That works if you have the room and time.

 

I used to hear the clunk until I figured out the best way to engage/disengage. No more clunk (unless I don't follow my own advice or can't based on the conditions).

Tips:
1. Make sure you're driving in a straight line
2. Make sure you're not under load when engaging
3. Must be doing a decent speed for it to engage faster (don't be doing 5 mph because it'll take longer at that slow speed...I'm usually doing anywhere from 20 - 40 mph)

With that said, straighten the wheel, and just as you flip the switch let up on the gas (almost lifting your foot off the pedal). Driving straight with the load taken off the drivetrain at the moment you flip the switch should engage it within 1 second without the thunk that everyone hears.

Do the same when disengaging and it should be silent.

 

Like I mentioned earlier.. Other 4WD systems (Jeep for sure) aren't so restrictive. They have a 4 high that must have more give in it. With Tacoma but not with 4Runner, it's no 4WD on dry pavement. It seems antique in today's world.. I'm not complaining about the truck, it just seems like they would have engineered this out by now, especially with all the traction control, lockers, etc.. It's like when it rains.. There was insulation in the roof of the 4Runner. Not the Tacoma.. The design team must say, "this is a truck, we don't need refinements like that." I guess.
Not bad, just different..

 

I hear you, my friend drove his F-150 from NJ to Ct (100 miles) on 4x4 locked. His manual also states he dont supposed to use 4x4 on dry pavement but us man we dont read no stinkn manual . I did the same when I got my truck just because I did not have time to read manual, the funny part after that my 4x4 never had any problems engaging.
Its says you dont supposed to use it on dry pavement but IMO that refers more to : 80F, highway or city.
Those trucks are very well build. I had seen them doing things that would make Toyota engineers go like "huh WTF" and still 4x4 system survived with no issues. In winter my wife drives my pickup most of the time and she does not go easy on that thing. She slams on 4x4 while having rear axle spinning like crazy. She does drive kids to school on 4x4 and dry pavement then says I forgot to turn it off. So if she did not broke my truck yet you will never do. I love her to death but she is horrible driver. I had to do suspension TSB because on our recent trip to OBX she drove truck like a dune buggy. I bet none had seen double cab long bed Taco clearing the air
So stop worring and enjoy the truck

 

You don't have to be moving that fast to get no clunk. Sometimes my 4WD will engage immediately while I'm at a dead stop. And then again sometimes it doesn't. It will reliably engage at slow speeds under the right conditions.

Lately I've noticed mine sometimes actually doesn't seem to want to engage while moving perfectly straight. It sometimes seems to engage while moving after I make a very slight turn of the steering wheel.

 

I don't think you should have to read the manual to figure out that you probably shouldn't drive a part time 4WD system on dry pavement.

 

Yeah after you own your first 4wd then no you don't need manual to tell you. if you live in NYC you own either 2wd or AWD. Everybody else own the same thing so you simply don't know any better.
Mr. Smarty

 

Thanks everyone for the good advise.. I was more curious than anything.
To be totally honest, I assumed the Tacoma was "past" this.

Not a big deal, no reason to worry, but certainly something to be aware of.

Our 98 Landcruiser is always in 4WD, with on/off for locking diffs, etc.. I'm sure it's a pretty stout system too..

 

My clunk went away after switching to redline gear oil in the tcase. Not sure about automatics, but even when stopped, foot on the clutch -no stress on driveline I would get a clunk but not after changing the fluid.