Need a 4 wheel drive lesson and when to use what

I just purchased a 2015 DC TRDOR 4x4 with tow package a few weeks ago. I have had no reason to go 4 wheeling yet. That will come in time but with all the additional "help" when 4 wheeling I am a bit confused so here are some scenarios and questions:

1. I've read that you shouldn't use 4 wheel drive on dry pavement roads. What if it is snowing but it's not like the whole road has a foot, just some slippery spots. Does this mean it's bad to go into hi4?
2. I know that I need to go into neutral for low4 and to not go over 15mph. Got that down
3. Let's say I'm on a steep hill that requires low4 and I still need help. Which should I use first, ATRAC or RR lock? Is there a scenario that's better for each?
   
4. Ok now for the DAC. If I'm on a very steep hill but it is dry and paved (happened this weekend out in western north carolina). Since I need to be in L4 to use DAC, I assume I wouldn't use it in this situation (just stay in 2wd and go to gear 2 or L) since L4 shouldn't be used on dry pavement - is this correct? Therfore, a DAC situation would more be used for off roading on a very steep trail?

Yes, I've read the manual but just trying to get some scenarios down which could come in very handy. I also plan on taking the Uwharrie Off Road training class in Troy, NC to get some tips also. Anyone done this class and will it be ok to use the stock tacoma for this? I've heard it's not extreme.

Thanks in advance

 

Lets go to URE, it's pretty tame.

 

1. It's ok as long as you are not making "sharp" turns. The driveline will bind because the wheels cannot turn at different rates. I drove from Raleigh to Shoe Creek with Jandrews and had such situations and I used 4Hi without issue, interstates don't turn too sharply.
2. Wrong, you can go faster than 15mph in 4Lo. Correct, To engage 4Lo you have to be stopped in Neutral.
3. ATRAC would probably be better as it will lock up the wheels that are slipping. RR lock will probably make you slip more. @jandrews told it to me best, "It's a game of alphabet soup".
4. I don't know the specifics on DAC, too high tech for 2006.

 

One thing to note, the front wheels are not powered when you are on the brakes/no power is applied. Even when in 4wd

 

A picture for 1.

 

The way I've always done it

2wd for dry pavement
4H for snow/ice on roads, off road slippery surfaces that low to moderately inclined
4L for the high inclines, I use 4L alot going down so I don't have to ride the brake (do not do this on pavement)
4L + ATRAC very difficult traction situations
* sometimes I go 4L and Rear locked without ATRAC depending on if the front wheels have enough or any grip
4L + ATRAC + rear locker, very steep, very little traction situation, very slow going, think crawling (or if I got stuck prior to engaging locker)

DAC-Rarely used it myself, Think of super steep offroad scenario, if you are on dry pavement you should have no use for this.

Edit:
also I believe ATRAC doesn't kick in above 3mph, but if you need it, you shouldn't be going more that. You can drive in 4L faster than 15mph, but personally when I'm in 4L the situation will be severe enough that you aren't going to want to go that fast

 

With respect to answer #1 (which I've heard before): so if the conditions are snowy, icy, muddy with inclines does the "as long as you aren't making sharp turns" still hold water? Wouldn't I want to be in 4 wheel drive in those conditions, sharp turns or not?

 

If it's not binding up the steering , it's fine

 

The problem lies in the driveline not being able to slip, too much traction at the wheels. If it's a low traction scenario then yes 4wd is fine, just be aware of when you are making turns if the roadway is dry/good traction.

 

Not necessarily binding the steering in 4wd from turning too sharp/full lock.

 

Say wat

 

We're discussing 4wd on high traction vs low traction surfaces and the rates the wheels turn at. Not if the steering binds up at full turn in 4wd.
OP: 4wd on high traction surfaces won't bind steering it puts stress on the axles and gears in the diff.

 

Terrain that warrants 4wd will also let the tires slip while turning so that you won't damage anything. If you feel like your binding then you don't need 4wd engaged

 

You can drive straight on dry pavement in 4HI all you want , it's when you are turning that issues occur

and you can turn on dry pavement in 4HI , turning sharply is when you can have issues

Thats what I was getting at

 

rgr, thought you were talking about a different situation.

 

use DAC (yes 4LO) for controlled downhill off-road situations. It is crawl control going down hill. It works great if it is slippery traction situations. Take your foot off gas and brake and the truck does the rest for you.

 

in theory you can drive in a straight line on dry pavement, but I wouldn't. Why would you anyway?

The issue you have is that in 4h you always have 1 rear wheel and 1 front wheel turning. If you drive in a straight line on dry pavement, you are assuming that your front and rear tire are being driven by your drive train at the EXACT same speed. There could still be a slight difference in the speed that your drivetrain is turning your front versus your rear wheel, the higher the speed the more difference there would be..... all wheel drive cars can do it because the have a center differential and not just front and rear.

 

The diff isn't made out of glass , it will be fine

 

The manual states to exercise the 4wd system 10 miles or so each month IIRC

If any slight driving on dry pavement , wet pavement or mixed conditions was going to wreck the truck , my diff would have detonated by now

 

I doubt you would actually feel it or see evidence on your tires especially if you only do it at low speed occasionally. I understand putting miles in 4wd. I'd just do it on gravel or something more forgiving just in case. The faster you go the more harm you could do.

My only first hand knowledge of this is on a couple of dodge rams I inspected. Both were 2500's, both blew up transfer cases due to being in 4h on the road.... but probably most important was that both were doing highway speed. (70-75)