4X4 High

Yes they have open front diffs.

But that has nothing to do with this. The issue is the locked transfer case. Subaru's and other AWD vehicles can turn sharply on pavement because they have a diff in the transfer case.

 

When I need to run it for 10 miles a month to lube everything.

 

The transfer case will explode if you even think about a slight turn in 4wd unless you are in deep snow or to the rails in gravel. A friend told me.

 

Whoever wants to use 4wd on dry pavement, you can do it as much as you want in your own truck. I will continue to NOT use 4wd on dry pavement because I live in a magical wonderland with a bounty of off-roading choices. There, debate permanently settled.

 

Strange... all i can find is information saying engaging part-time 4WD on dry pavement will cause damage. Anyone ever read anything stating otherwise?

 

Sometimes slickrock is slick, that's why it's called slickrock.

 

The slick rock in moab has tons of traction. Similar to brushed concrete.

 

This.

I turn it on when driving around and take turns wider based on how the steering feels. For pulling into a parking spot or any tight turns I pop it back into 2hi.

 

My '04 I used to just use 4wd when I needed it. I wouldn't doubt I went a whole summer without touching it. Yes, it is certainly good to warm up and use the lube every once in a while, but my 230k mile '04 is living proof that NOT doing that religiously is not going to kill it.

 

I also engage mine on dry pavement. But I also engage it in the rain, snow, dirt, mud, whatever. I don't do it for 10 miles a month, maybe 1 mile a month. But then when I'm off road, I might just leave the 4wd engaged the entire time. No issues here.

I'm with Oz. I occasionally will turn , but I make wide turns and try to avoid them. I figured it was better to turn in 4x4 rather than disengage while in the middle of the turn.

 

This is my first 4 wheel drive vehicle. This thread is the reason I have been surfing this site and reading a lot.

You guys are a wealth of information. Lots of stuff I did NOT know...

(you could fill a house with stuff I don't know)

 

OH NOES! You has voided your warranty!
Just kidding. Although I'm sure the dealership would tell you that if you blew a hub doing it, haha.

I also engage mine once a month to keep things lubricated, on pavement, while driving in a (mostly) straight line at about 35-40mph. Never had any problems result from it, with any vehicle.
OP, the idea that 4wd locks all four wheels together is a misconception; the spider gears in your differentials still function as normal, allowing for some difference in wheel speed from one side to the other, even with 4x4 engaged. Engaging 4x4 locks your front HUBS, not your differential. Those of you with the TRD offroad have the option of mechanically locking the rear differential, during which the spider gears cannot spin to make up different wheel speeds, which is why they specify only engaging the rear locker in low traction, low speed situations (and why you can only engage it in 4-lo from the factory; to minimize driveline stress).
Driveline bind only occurs when you're turning sharply in 4x4, when the spider gears in your differentials can't make up the difference in wheel speeds.


Edit: here's a handy-dandy visual aid of how an open differential (one without a mechanical locker) works:
http://auto.howstuffworks.com/differential2.htm

 

So much drama in this thread...

 

I'll start of by saying that I'm not horrified of driving in 4wd on pavement. Do I do it, no.
The statement of the differentials not being able to make up the difference in wheel speeds is incorrect. The problem with binding occurs when the overall ratio's front to rear are different, i.e. when you are turning. Your track front to rear is different, with the front attempting to travel further than the rear. Without a center diff to make up for that, it binds. You can be locked f&r or open and it will still occur without a center diff.

 

I LOVE TW! Y'all are awesome! Thanks for the great advise and laughs. I am enjoying the tit for tat. Next I need to find the closest trails to Lafayette, LA.

 

Yes, sharp turns induce different axle speeds as well, which are transmitted through the driveshafts into the transfer case. Modern transfer cases have their own differential to allow for some difference in axle speeds, but sharp turns produce more of a difference than they can account for. Unless you have an actual locking center differential, some difference in axle speeds is negated by the T-case. The T-cases on our Tacomas (I believe) utilize the differential in 4-hi but not in 4-lo. (any Toyota techs who can confirm/deny this? They may utilize it in 4-lo as well...)

Edit: As an example, here's a transfer case (in an 80's Dodge) that lets you lock the transfer case so that there is no allowance for different speeds between the front and rear axle.

 

My 2012 is modern, with no center diff. Therefore no way to differentiate speeds from front to rear. These are not AWD trucks, they are 4WD, big difference.

 

So OP, what are you going to do??!! Lol are you confused yet?

I go all summer never engaging 4WD, even longer really. I only use it when I need it so Dec-April.

There are, how many members on TW? That many answers to your question! Haha

 

I was under the impression that the planetary gearset in the transfer case mitigates small differences in the rotational speeds of the front and rear driveshafts.

 

Our cases are chain driven, no planetary gear set.