4x4 useage.

Tundra Jerk · #1 (**permalink**) 08-31-2002, 06:06 PM

Sorry if this has been covered but.........is it nessesary to use Hi4 every once in a while just to keep it problem free?I searched the threads but got nothing.If so, how and how often?Is this true with Lo4?Can I engage Hi4 on dry pavment or should I wait till Im in dirt or sand?Thanks.

TMS2U · #2 (**permalink**) 08-31-2002, 07:23 PM

Generally you need to use 4x 10 miles/month. That can be either 4lo or 4hi. This is so that the tyransfer case and front diff remain properly lubed.

Tundra Jerk · #3 (**permalink**) 08-31-2002, 08:19 PM

Can I use Hi4 on the dry pavement?

KLS · #4 (**permalink**) 08-31-2002, 08:27 PM

No. You must be on a surface where at least one wheel can slip--sand, loose gravel, mud, snow, etc.

Ken

wlafed · #5 (**permalink**) 08-31-2002, 10:11 PM

That's not totally true. You can drive on a dry paved road in a straight line with minor curves.. Just don't try to parallel park on the dry pavement or something like that. No extreme turns.

tiger · #6 (**permalink**) 09-03-2002, 12:18 PM

I read in the owners manual that 10 miles a month would keep the parts lubed and just highway driving should do it! I took mine out last night to do just that.

TIGER

nhparrot · #7 (**permalink**) 09-03-2002, 12:26 PM

I asked one of the Master Techs at my dealership about this recently. He confirmed member wlafed's response. As long as you are driving on a straight road - you are fine.

KLS · #8 (**permalink**) 09-03-2002, 12:47 PM

Quote:

Originally posted by wlafed
That's not totally true. You can drive on a dry paved road in a straight line with minor curves.. Just don't try to parallel park on the dry pavement or something like that. No extreme turns.

You're right, of course...but that advice is reliant on the driver remembering that he's in 4wd, and remembering to keep the steering wheel straight, and hoping that he doesn't need to turn even moderately. Too risky for lots of us.

Ken

staggarlee · #9 (**permalink**) 09-03-2002, 01:06 PM

What exactly is going to happen if you run the 4WD on dry pavement?

Genthar · #10 (**permalink**) 09-03-2002, 02:07 PM

From what I understand, the 4wd relies on some of the tires being able to slip a bit when necessary to keep things from binding up. On dry pavement they don't slip too well, and can cause excessive wear and stress on the 4x components. Primarily you're gonna see this in tight turns. There are others that know more about what happens than I do...I just remember that 4x + tight turns + dry pavement = bad.

KLS · #11 (**permalink**) 09-03-2002, 03:03 PM

If you see the tire tracks on a surface that shows them well while you're making a tight circle, you'll see four separate tracks. That means that each tire is turning at a different speed, the inside tire slowest and the outside tire the fastest. Your differentials allow for the speed difference for the two wheels on each axle, but you need something to allow for the speed difference between the front axle and the rear axle. Something has to slip. Some vehicles are equiped with a center differential, or viscous coupling, or some such gizmo. Not our trucks.

If you make a tight turn on a firm surface, you'll notice that things bind, hop, etc. Usually you just get increased tire wear. If you're unlucky, something mechanical breaks.

Ken

arkie6 · #12 (**permalink**) 09-04-2002, 12:21 AM

Quote:

Originally posted by staggarlee
What exactly is going to happen if you run the 4WD on dry pavement?

Best case? Nothing.
Worst case? You break something in your driveline.

It's a gamble I'm not willing to take.

redbaron224 · #13 (**permalink**) 10-01-2002, 07:21 PM

Quote:

Originally posted by nhparrot
I asked one of the Master Techs at my dealership about this recently. He confirmed member wlafed's response. As long as you are driving on a straight road - you are fine.

Also note that binding can be created by having a different effective tire diameter. Even with equal tire pressures you can't be sure the effective diameter of the front and rear tires will be equal and prevent binding in the transfer case. For instance, with equal tire pressures and sizes, the "extra" weight of the engine in the front will reduce the effective diameter of the front tires, causing them to rotate faster than the rear. This difference can add up in a hurry, even much less than 10 miles.

You can prove this by installing dramatically different tire sizes front to rear, not that one would want to do this and risk severe and expensive damage to the driveline though. :-)

This is also why vehicle manufacturers stress the importance of running equal size tires side to side. Excessive mileage with two different tire sizes on the axle will lead to premature spider gear wear and failure.

tundra-gearhead · #14 (**permalink**) 10-02-2002, 01:42 PM

Isn't the 10 mile a month for 4x4 systems with manual locking hubs? Since your not spinning the front diff when the hubs are unlocked? Our 4x4 Tundra's are always pushing the front diff hence the poor gas mileage. The only thing I could think of would be to spin gears in the transfer case.

Genthar · #15 (**permalink**) 10-02-2002, 01:53 PM

It's listed in the Tundra manual to do the 10 mile thing...now whether or not that's necessary or not is another matter.

I do try to do the 10mi/month thing myself...