Getting 10 mi/month in 4WD

I had my FJ for 2 years before going on trails. Never used the 4hi/4lo until then. I didn't have any problems shifting to 4hi/4lo and did great on the trails. However; I have used the 4wd when it rains, roads are wet, and in the snow. I am hoping the 4Runner will not have any issues since it would be the situation as the FJ when I am ready to take it onto the trails. Bought the 4Runner in 2020 and still did not use 4hi/4lo.

 

It probably won't be an issue until many years. The sensors in the transfer case get corroded, or maybe it's better to say they blacken over time without the friction of regular use. Unfortunately when dealing with electronics 4x4 systems, when the sensors don't work, the systems don't work. Of course, if you have a lever like the TRD models, you will never have a problem physically shifting into 4hi or 4 lol, but using your rr diff lock, or atrac is a different story. So to be honest it is probably sufficient just to physically go through the shifting motions a couple times a month. In fact if a sensor goes bad, the first fix to try is shifting rapidly in and out of 4wd just to try to degunk the sensor. Anyway it was 15 years before I had a problem engaging the diff lock on my FJ, which I only very occasionally used before it failed to engage.

 

Oh yeah and there's a sensor back in the diff for to tell the computer when it's engaged

 

In post #22 I posted a Car Care Nut video. From around 6:00-10:00 he explains the 4wd mechanism & why it should be exercised. Usually people take his advice as solid, so...

 

Yeah, I had seen that one before and watched it again when you posted. Among the things he mentioned as potentially seizing from disuse were the actuators controlled by the ADD. It was worth watching again to catch that.

I plead guilty to watching countless Car Care Nut videos once I decided on the 4Runner.

 

You'd be surprised. You can almost take a 90 degree turn at a normal intersection in 4hi, even on dry pavement.

Do yourself a favor. Find a fairly empty parking lot, shift into 4hi and drive around very slowly. Make a few gentle swerves left and or right. You'll be able to to feel and hear when the drive train is starting to strain or bind and then back off the turn a touch. You can do this a few times and get a feel for how much is too much.

I must caution you though. Take it very slow (1 or 2mph) and turn the wheel very slow until you get a feel for it.

As others have said, I throw it in 4hi anytime it rains or is even slightly wet pavement on my way to or from work. I don't have any straight stretches of road on my commute either (curvy country roads). The wet pavement is just a reminder for me. The curves aren't so tight that I'd be concerned about the drive train binding. I just make sure to shift back to 2hi before I make the turn onto another road.

 

Central diff lock will lock front and rear drive shafts. But the front and rear diff are free, which means all 4 wheels can spin at different speed. So why does gear bind while turning with central diff lock?

 

This is my favorite explanation of windup. The best use ever of Lego.

 

Great movie. I need one of those Lego models.

 

I played with the 4WD today on some straight bits of pavement. Throwing the shifter in either direction took some getting used to. Next week I might head for the little stretch of gravel up at the Delaware Water Gap.

 

If the center diff is locked, the t-case acts exactly the same as a part time transfer case - the front and rear driveshafts are mechanically locked together and must turn at the same speed.

With the center diff UN-locked, that mechanical connection is disengaged and the driveshafts are free to turn at different speeds.

Note that the only 5th gen 4R to have the center diff lock is the Limited. The other models have part-time 4wd systems.