Hi there,

I have a 2017 forerunner with about 40k miles. Admittedly I don't use the 4wd as much as I should. I've had Toyota pickups and Subarus, but this is my first vehicle with an automatic transmission where I have to engage the 4wd.
So, here's the scenario and my question:

1) I thought I'd engage the 4wd recently on a steep, paved road, just to use it for a bit.
2) Going slowly, I turn the dial to go from H2 to HD. It engages fine.
3) But then, when I'm cutting the wheel on a turn, I hear (and feel) a grinding noise, and the steering wheel kind of snaps back and is hard to turn.
4) In reverse, it almost feels like the wheels jam up.
Have I done irreparable damage? Something wrong?

I have since read that you shouldn't use the 4wd on pavement with forerunners. If so, that's a little bit of a bummer, because I do like the better handling.
If this is the case, can you engage the 4wd on wet pavement, like in rain?
Thanks!

Driveline bind. Part time 4wd has no center diff so the wheels cannot turn at different speeds like they do when you make a turn. Perfectly normal and ok for the most part unless you're on a high traction surface.

Thank you--good to know. Is this something that requires a repair, possibly? Or something I just shouldn't keep doing? Like, I should put the truck in 2wd when making turns?

With part-time 4WD, it's best that you don't use it on surfaces where you have a lot of traction. Turning on these surfaces will cause the driveshaft to bind and is likely what you're hearing/feeling. The Limited trim 4runner has full-time 4WD which has a center diff and allows for use on high traction surfaces (basically it acts like AWD). If you didn't use it for a 1000 or so miles, I think you'll be fine. I have left 4WD on a few times after leaving a trail and it has been ok. Only noticed it when I made a sharp turn and the wheels hopped/binded.

Regarding in rain, the 4runners traction control works pretty well so shouldn't need it. Arguably can cause more issues since both front and rear driveshafts are spinning at the same speed. That being said, in the worst of conditions, I have put it in 4high and then turned it off when turning.

i really wish they didn't remove the "too much friction" video from youtube

(also it's very "on brand" that the users from southern CA think you need 4wd for rain :wink

I think I'm a little bummed out because this truck gets super low miles per gallon, and I wish that I could at least get awd out of the deal. But I should have researched the Limited version more, I guess! Because right now, I get maybe 13mpg and basically just have a really heavy 2wd vehicle! It's sure pretty though.

13 mpgs! you might have other issues.

Yep, I just did the math. I filled up yesterday--the tank was close to empty but not quite. The tank is 23 gallons, and I got about 303 miles before filling up. So at best, if there were still a few gallons left, that's about 14mpg.

I have wondered if there's another issue going on--I agree with you!

LOL! Actually I'm originally from New England, and I'm so desperate for precipitation that I celebrate rain by trying to engage the 4wd. Kind of sad, I know!

Limiteds are AWD.

Now now, we freak out and think its a blizzard when its 69F and its a heat wave when its 71F lol

14mpg ouch. I'm getting at least 340-350 miles to the tank!

SpeedyKevin, good to know... I think I'll bring mine to the dealer soon for a tune-up, maybe get some new spark plugs. I'm due for at least an oil change, and at 40k miles, maybe a tune up as well. I'd like to be getting at least 15-17mpg with just 2wd engaged.

Yes, I just have the SR5, not the Limited. I also wonder if the Limited gets better mpg with the AWD!

Sounds like he is operating in 2WD as well so it does not sound like he has a Limited?

But yes, the limited has the option to unlock the center diff, which makes it like any other AWD vehicle and operates on-road or high traction surfaces just fine.

Locked center and it operates just like the rest of the 5th gen lineup in 4WD.

Clarification by the OP in the beginning would have been more productive.