C6 Doberman

I have to run some parts from Atlanta to Charlotte this afternoon. Is it okay to drive in 4HI for long periods? I just bought this truck and I don't want to break it just yet.

Bottom Dollah

I picked up my XLT on Feb 2, 2010. Feb 3 brought rain, freezing rain, 10" of snow and sub-zero temps.

I made a 180 mile trip, right in the middle of it (Court Date) and drove in 4H the whole time. No adverse effects.

mlts22

Depends on the terrain. It isn't good to run in 4x4 mode constantly when on a road because the wheels can't slip. Also, if you are running the engine, even at idle, you are definitely breaking it in.

SultanGris

he said he didnt want to break it, not break it in, haha!

kozal01

iTrader: (2)

as long as its not on dry pavement you can run it as long as you want.

rkfvd3

Yea I haven't taken mine out of 4 high since two nights, which has been about 500 miles. I hope you don't have pirelli tires bc the really really suck in snow. I'm glad it's been an easy winter in the Midwest or I would have bought new tires already

texasgator

We don't get snow down here in Houston, but when we get pouring rains I'll use it. Used it a few times on the freeway at around 60 mph for 20 miles, no problems.

Rob the elder

The differential compensate for the fact that when traveling in anything but a straight line, the inside wheels and the outside wheels are traveling at a different speed. If the differential was not "open" then the two wheels would be solidly tied together and the outside wheel which is turning faster because its on the outside of the circle, would be trying to spin the inside wheel. This will result in tire scrubbing and excessive mechanical wear until the weakest component between the two wheels breaks.

With the open differential on both axels the left to right differential speed is not an issue. But since the front and rear differential are tied together mechanically when in 4 x 4 mode, there can be a different speed between the front axel wheel pair and the rear wheel pair that gets fed through the front and rear draveshaft and into the transfercase. In "full time" or "realworld" four wheel drive, the transfer case is actually a differential and will accommodate mechanically for differential speeds between the front and rear. In our trucks without full time four wheel drive, the transfer case is a straight pass through of torque from the transmission to the two drive shafts. When in anything but straight ahead travel, there will be a differance in speed between the front and rear. On rough or low friction surfaces, like snow, ice, sand or mud, the differences will build up until one of the least loaded wheels will "slip" and unwind. It happens frequently depending on how big the difference is between front and rear wheel pair. If there is firm, dry pavement under the wheels, then all the load gets transferred to the drivetrain, and will result in excessive tire wear at the least, and under prolonged use, the weakest component of the drivetrain will fail - by throwing itself at the ground and leaving you with a broken truck. If you are lucky it will be a U joint. Worse case is you are out a couple thousand for a new transfer case and U joints.

If you want to test this, take the truck to a parking lot with a little sand or light water. Put it into 4 wheel drive and make a very slow tight turn. You can hear and feel the wheels hopping as they slip and unload the drivetrain.

Driving in loose terrain, or in snow or ice can be done . .. basically for ever. The drivetrain is designed to operate this way.

Driving on solid or non-slippery terrain in anything but a straight line will eventually destroy your drivetrain.

mlts22

Complete misread on my part. I was scratching my head about this big time.

As for the topic at hand, I'd love to see all F-150s have AWD. This way, true 4WD can be an option, but for most cases, one can just leave the transfer switch in AWD, let the truck figure out when to bring all four wheels online.

techrep

iTrader: (1)

In the snow go for it...it's very easy to switch back and forth...a flip of the switch.