Binding 4x4 on pavement question

I have a TRD Off-Road. I know you're not supposed to use 4x4 on dry pavement.

I'm just wondering why it binds? My understanding is the front is an open differential. Why would it react differently than the rear axle where the wheels turn at a different rate when in a turn?

 

I'm pretty sure it's the transfer case that doesn't allow it. The mechanics of it escapes me ATM.

 

http://auto.howstuffworks.com/four-wheel-drive.htm/printable

 

The bind is not left to right but front to back as I understand it. You are right- The open diff allows the drivers and passenger sides to spin at different speeds. But there is no inter-axle differential...so the tires need some latitude to slip when both the front and rear diffs are tied together.

 

Cool, thanks everyone. I thought it was a left-right bind issue but it's a front-back bind.

From the article:
The transfer case on a part-time four-wheel-drive system locks the front-axle driveshaft to the rear-axle driveshaft, so the wheels are forced to spin at the same speed. This requires that the tires slip when the car goes around a turn. Part-time systems like this should only be used in low -traction situations in which it is relatively easy for the tires to slip. On dry concrete, it is not easy for the tires to slip, so the four-wheel drive should be disengaged in order to avoid jerky turns and extra wear on the tires and drivetrain.

 

Full time 4WD or AWD has a third differential that allows the front and rear driveshafts to rotate at different speeds= no binding. Off road rigs with full time systems have a differential lock-out for serious off roading where you want an even split between the front and back driveshafts... AWDs that don't have the center differential locker have unequal split of power to the front and rear.

(yes, I know it all is in that great link.. I just like typing it out )

 

power goes 50/50 front and rear but the axles follow 2 different paths on a corner. the front axle will be out wider than the rear axle if you hold a turn and look. That is essentially 4 different diameter turns for 4 different tires. With more traction pavement allows stress builds until released......hop hop hop This getscompunded with locked diff. that wont allow left /right speed differences. Mine has 2 open diffs , the bind comes from a fron and a rear tire with the most traction ... one releases eventually.

 

You must also understand...

When you make turns while in 4WD, the CV JOINTS bind up.

 

Just wondering if you put it in 4WD on pavement and turned or backed up and turned will it wreck anything?

 

http://www.youtube.com/watch?v=K4JhruinbWc

 

If you did it a little bit it probably wouldn't hurt it but it's definitely not good for it as it puts a lot of strain on the drivetrain.

 

Dont turn sharp in 4wd on pavement. Switch to 2wd for that.

 

Personally I would never have the 4wd engaged on pavement (except snow or ice.) If you feel the need just be careful and make very gradual turns...
http://www.4x4abc.com/4WD101/axle-wind-up.html

http://www.4x4abc.com/4WD101/def_turnpart.html

 

Guys... 4WD is for when 2WD won't drive you any further.. at least for off the dry pavement. Since turning your truck on dry pavement does not require 4WD, that is a good indicator to not put it in 4WD. It is so difficult to turn a truck around on dirt in 4WD, I put it in 2WD when steering is difficult.

 

Clearly the Tacoma 4WD should only be engaged on slippery surfaces, not on dry pavement. What I find amazing is that Neither the 2010 manual nor the dealer tells you this. Particularly when the manual directs you to drive in H4 for 10 miles once a month to lubricate the system, they should advise that you should only do this while driving in a straight line or off road, preferably both.

The way the manual reads, you'd think it is no big deal to drive in 4WD mode whenever you feel like it.

 

As soon as you try to steer in 4WD, on dry pavement, you will know you shouldn't be in 4WD! If it is hard to do, then find an easier way!

 

My 4wd use is mostly when driving in the snow. And I LOVE the challenge of "can I make this in 2wd???" I enjoy challenging my truck and quietly beat my chest when I make it in 2wd. But if I am stopped and can no longer move forward in 2wd, I switch to 4wd and usually ease right through it (or up it).

The problem is when you are tracking on something that requires 4wd and forget to switch back to 2wd when you reach pavement. Of course you will know it when you try to turn but...its not good for the drivetrain.

 

No kidding! Although I only noticed it while parking (sharp, short terms is probably why). It was as if the emergency brake had just engaged, or I had suddenly encountered a steep wedge of ice.

Toyota makes this issue very clear in its instructional material it provides to dealers and sales reps. Why not include it in the manual? The manual doesn't even tell you the location of the oil filter or oil drain plug, so I shouldn't be surprised.