4wd sharp turn on pavement

I did something stupid.

I am new to the truck world and 4wd. Today it was raining very hard here in austin, texas. When I was driving my 09 tocoma 4x4, I decided to try the 4wd out.

I read the manual before and know it's ok to switch between 2Hi and 4Hi "on the fly" as long as at speed below 62 mph. During driving on wet pavement I switched a few times, I didn't really feel anything bad I even drive in 4Hi on highway at 65mph for about 15 minutes. However, when I was making sharp turns and parking at a parking lot in 4Hi, in at least 3 occasions, I felt the steering is really hard and the truck slided sometimes. Now I know I shouldn't drive my truck that way and part time 4wd is not designed for pavement. Too bad the manual doesn't say that.

Anyway, what the worst I should expect to happen? Is there anything that I can check for the damage that may already be there?

 

nothing bad happens, just dont do it often. Thats just your truck pushing your front tires sideways since the front is "locked" into 4wd.

 

After driving I read a little bit about 4wd and realized what was wrong.

 

Definitely, do not use 4wd on dry pavement, unless you plan on driving in a perfectly straight line. If your tires aren't allowed to give a little, be it on gravel, dirt, snow, etc., the drive shaft will experience a torque caused by the front and rear axles rotating at slightly different speeds. If the drive shaft were strong enough, and your tires didn't slip on the road, and you decided to take a turn going 65mph, your drive shaft could build up enough spring force from being twisted, that the truck would flip itself to release the torque. In a real world situation, you would probably just break a u joint or another part of the drive line if the tires weren't allowed to slip. This is why they advise you not to drive 4wd on dry pavement.

 

Good explanation!!!!!!!!!!!!!!!!

 

Patient: Dr! Dr! It hurts when I do this.

Doctor: Don't do that.

 

I didn't go to college for nuthin'

 

haha precisely

 

I've never turned going that fast but do turn in 4wd and feel the 'push'. Sometimes you can't avoid it.

If theres snow on the ground, I will use 4hi to pull out of a driveway or something. I have to turn onto the road, which is clear and I feel the push. Once I straighten out, I drop back to 2wd.

I don't think there is any other way to do this and can't imagine i'm going to twist a drive shaft doing this...right? I don't do it often but sometimes you have to and it is always at a crawling speed.

 

Thanks for all your inputs...I've learned the lesson. I did drive at 65 mph for about 20 min and make several 90 degree turns at about 10 mph and park in the parking lot for a few times on the wet pavement.

I actually do not feel anything wrong right now, but some parts on my truck may need replacement/repair sooner than they suppose to be. Is that the situation I am in right now?

 

At crawling spd you should be fine. I have had trucks on dry pavement in4wd and if the tires do not give and u are going slow, the drive line will bind up and stop the truck. U will most likely do no damage at crwling speeds

 

Maybe in my case, the tires actually gave because of the water/moisture on the pavement. I felt bumps a few times at some turns but the truck continued to move slowly. I also felt the steering heavier.

It was the first time I tried a 4wd, there was actually nothing scary enough to make me think it was not normal, I had no idea on what it should be. After the driving, I was thinking 4wd is rough.

 

Just try to use it for offroad and snow. And remember u will have understeer aka front tires will push or plow when turning

 

Locked is a little misleading, as nothing is locked, but rather engaged. Not to mention there is no locker in the front.
Post #4 described it best http://www.tacomaworld.com/forum/2nd-gen-tacomas/30209-4wd-sharp-turn-pavement.html#post464071
It's just the binding of the front and rear, with no slip in the transfer case, which AWD vehicles have, hence the reason they do not bind like part time 4x4

 

I drive mine at 65mph when it rains just to keep the 4WD system running and lubricated (so to speak). But as soon as I get on the exit ramp, I'm back into 2WD. Going straight is one thing but making turns is a bad thing on pavement.

Have you engaged/disengaged 4WD since? If you're able to get back into 4WD without any problems - then I'd say, your truck is OK. I'm sure you didn't mess something up.

Making tight turns in 4WD is NOT good anytime or anywhere. CV joints don't like that.

Anytime you find the truck bucking, hesitating, or acting weird while in 4WD - don't push the issue. Back off....straighten the wheel out, go in reverse, take it out of 4WD whatever. Don't ever force it againest its will!

 

AWD drive vehicles have a center differential between the front and rear to allow for the two axles to rotate at different speeds. true 4wd does not have this, as mentioned above. check out this link for further explanation.
http://auto.howstuffworks.com/differential1.htm

 

Thanks man. Yes I still be able to engage/disengage 4WD. In 2WD I don't feel anything wrong. The ride is still smooth without abnormal noises as far as I can tell. Acceleration and shift of gear feel normal too.

I call my dealer today. He suggests me to drop the truck to him for a inspection. Too bad I am too busy so I have to wait to next Friday or so to have time to do that. I will keep normal driving in 2WD until then. I hope nothing serious will happen.

I will keep you guys informed.

The last question, if there is already something damage, let's say the CV joints, or some part in the drive-line, what typical signs should show up? noise? vibration? being unable to turn? being unable to engage/disengage 4wd?

Sorry about the stupid questions, this is my first truck and my first 4wd, I am trying to learn.

Do you guys think it will be safe to drive in 2wd until I have time to have it inspected?

 

zhaoz,
You can drive the truck in 4 wheel high you just can't go crankin the steering all over the damn place! I routinely pull my 1994 up into 4 Hi on dry pavement just to get the oil moving about especially during Summer months.

 

My service manager arranged a technician to inspect the vehicle. He told me that the technician test-drove the truck and visually inspect the bottom of truck and didn't find any problem; he also read the computer for error codes and didn't find any. Basicly, he thinks my truck doesn't appear to have any problem.

I hope he is correct but anyway I have learned "no turn on pavement in 4wd" and it's time to move on.

Thanks again for all your inputs.

 

Hi! Tig1 calling--so the manual says to run in four wheel drive for 16 miles
to lube up the parts.but I don't have that kind of area to drive in.so running it on pavement in a straight line is ok? does it have to be that far? what about 4wd in low?