Ever turn on 4-high while going 60mph?

Hi TW,
I was reading the owners manual (because I'm a nerd) of my 2016 and it stated that 4-high could be switched on while going ~60 mph. I was going to try that this morning while driving to work, but chickened out. I'm sure it's safe, otherwise they wouldn't have put it in the manual. I'm not sure what real-world solutions would call for this, but I'm sure many have done it.
Have you done this, why, and did anything unexpected happen?
Thanks,

 

60 mph is the max you want to be going while switching into 4-high. I'm guessing it might be useful when encountering slippery road conditions while going highway speeds.
I have not done this going that fast, but I have done it around 40-45 mph.

 

i have, just make sure you are cruising or coasting and it will be fine.

 

Yes, it just beeps and blinks at you.

 

i do all the time as you describe. it's seamless, no problem at all. you don't even feel it if you're off the throttle, which of course you should be.

 

If you have to wonder if you need four high, you already should be going slower than normal. If you have to wonder if you need four high, switch to four high.

 

The manual states that you have to be below 62mph when engaging 4HI. You can go as fast as you like when in it though. I've had mine up to 80MPH. Your not going to break it, just don't do any crazy maneuvers or sharp turns

 

this.

I haven't tried it, because I haven't been in the situation to need 4hi while doing those speeds. To me, if you need 4hi to keep traction you shouldn't be going those speeds anyways.

Think the fastest I was going and turned it on was around 40km/h. Too much snow, so just switched over to 4x4.

 

what's the point of being in 4x4 at those speeds? Unless this was desert racing I don't see the point.

 

To exercise the front diff, manual says to go at least 10 miles per month just to keep the 4HI lubricated. Well I don't go off roading often enough to fill that quota so whenever the streets are wet here I put it in 4HI on my drive home from work just to exercise it.

 

because it gets you your requisite 50 (or however many) miles/month of 4x4 real quick like! lol

 

I'd be worried about causing damage though doing that.
But to each their own.

 

I don't see why. It's a 8" diff just like the rear (for 3rd gen sport models anyway). You'd think if in anyway it could cause damage Toyota would put some sort of safety to auto disengage at a certain speed. But to each their own, if you don't feel comfortable doing that by all means don't do it. You shouldn't ever do anything to your truck that you don't feel comfortable with.

 

Has anyone noticed any difference in gas mileage when you are in 4x4 HI ? If yes, how much of a delta is it?

(Also, isn't there a thread here from a while back who broke his front diff doing normal 4x4-ing, and when contacted Toyota and they responded basically 'no mas' to him. Got told that he shouldn't be doing 4x4-ing. He had pictures and everything, there was some piece made in plastic that broke off. I can't find that post)

 

I'm neurotic about damage and that kind of thing. when i do that it's on a very wet road and only in a straight line. if there's a bend in the road i turn off the 4x before it.

 

It just makes the steering stiffer. Did it on the freeway.

 

its not the speeds I'm concerned with its too much grip and causing damage lol.
Rain isn't usually enough unless its really pouring to allow the wheels to slip.

 

YES! I'll get about 15 - 16 miles to the gallon depending on how hard you push it. But again the 4HI shouldn't be driven engaged all the time, just when traction is an issue or for exercising the system

 

I would agree with you on city streets, rain isn't enough to allow slippage, but on Highways I've never felt any kind of binding

 

I actually get better mileage in 4high. Speeds are generally less than 55mph. At 80mph the truck is using more fuel in 2 wd.

I've noticed this with my 2nd gen Tundra as well.