Ant

Don't laugh yet.

Today we had the first rain of the season and buzzing across town I was slippin n sliding with every turn (new tires still not broken in)

Then the little light in my head went off: turn the knob to H4 and hit the diff button! Low and behold, hanging turns in the rain and gripping the pavement like it was dry. This is my first shift on the fly rig so I guess now I've gotten with the program.

OK, now you can laugh

03 4Runner

I just got my rig too. I just turn 1K miles today.

I think you would get better handling not locking the center diff.

Ant

By going from H2 to H4 and locking the center diff I get traction with the front and rear end. By just going from H2 to H4 and NOT locking the diff I'm still in 2WD correct?

03 4Runner

H4 will give you 4 wheel drive similar to the new AWD systems on the newer pavement only SUVs. The center diff lock gives you better forward traction, but the problem comes in lateral traction when you turn. In a turn all four wheel are ratating at a slightly different speed, the center diff is there to allow for differences in the wheel rotation between the front and the rear, just as the front and rear diffs allow differences from side to side. If you lock the center diff it will the front and rear drives will be locked together (which is better for forward traction and wheeling). The locked center diff stop the front and rear from turning against each other, thus the only way the differences are relieved is by the tires slipping which is not so good for lateral traction. On dry pavement this will cause high stress on your drivetrain as the wheels cannot slip to relive the stress.

Hope this helps. I think there is a writeup on this site on how this works if My rambling is to confusing.

FirstToy

Yeah, if you're ON pavement (rain, slippery conditions) turn to 4Hi. That way you have VSC do what it's supposed. You could leave it in 4hi all the time if you wanted to. Just 4Hi allows the Torsen to transfer power to whatever wheel it's needed instantly to all 4 wheels.

OFF pavement, 4hi or 4lo and lock the diff. That way you get max traction for wheeling.

Locking the diff on pavement can cause driveline binding like 03 Runner described- not good.

Ant

Thanks for the explanations! Now it all makes sense, H4 on pavement and DON"T lock the diff.

4runner4life

this website give a pretty good illustration of how differentials work.
http://auto.howstuffworks.com/differential2.htm

4runner4life

I dont know how you went that long without trying the 4x4 options unless the book recommends you not use it until a certain milage. I wish I had a rear locker.

Ant

Cuz I'm a dumbass?

Ant

Thanks!