Have a noobie question, from searching i see lots of posts advising NOT to drive 4x4 on dry pavement, fair enough. Couple things that i could not find definitive answers on were:

1) Does repeatedly switching from 4x2 to 4HI cause damage? (i only switch back and forth because of my next question)

2) when coming off a snow/ice covered road (neighborhood roads) where i cant drive straight without 4x4 and entering a major road where there is snow/ice on the shoulders and on the street but mainly the tire paths have cleared where you can almost see the pavement, is it bad to stay on 4HI? going speeds up to 80km/hr (50mph).

any input would be greatly appreciated.

 

If memory serves, 50mph is about the limit in 4HI to not cause damage or severely increased wear.

Consulting your owner's manual for 4WD operational speeds should put any doubts to rest, however.

 

1.) Damage, not really. Increased wear and tear, sure. However, one might argue that shifting frequently might be better than the opposite, when you go a year without ever shifting and things seize up.

2.) if you are going over sections of road driving straight when a lot of the area is snowy and what not, shouldn't be a problem. 50mph... Yeah I think the owner's manual consults this but FWIW I've had trucks for a long time and have done plenty of driving at 70mph with it in 4wd and no problems...

 

The top speed in 4WD is limited?? I am glad that I saw this thread, as winter up here can be a challenge --- even on the freeway...I'll have to consult my owner's manual on this issue...........

 

I dont think top speed is limited, it's just limited for switching from 2 to 4 WD.

I always have and will put it in 4hi and 4lo and drive around a couple times of the year. This will lubricate and keep things working smoothly.

I switch from 4 to 2 and back driving on the roads when it snows here. Dont think you will wear anything out just using it for driving in snow.

4lo is a different story and having the electric transfer case shift is nice because you could really Eff things up trying to put it in 4lo while moving at higher speeds!

 

Actually no you cant wreck anything switching to 4 lo at a speed. it will not do it until you slow down to i think 5 km/h is that is said on the dash last time i tried it

 

I think that's why he said it's nice having the electronic shift.... it won't let you eff up by trying to do it at higher speeds by just pulling harder on a mechanical shift lever....

 

I dont think you can shift to 4lo with mechanical shift...my 2009 has the mechanical shift and it makes me put it into neutral before shifting to 4lo from 4hi.

 

I have been driving 4x4 F150s since 1974. Back in the day . .. LOL . . on a snow day I would have to turn in the front hubs in the driveway before I went to work. Then I would shift (all were manual on the floor then) between 2x and 4x depending on the road conditions. With snow / Ice, into 4x, dry pavement, 2x.

I have followed this practice on every 4x vehicle I have owned including F150s, Wagoneer, and Ranger. Never a problem.

If you think about it a bit, the front drive train is a differential connected via CV joints to the wheels. And driving it is the transfer case (basically a standard gear box) connected to the same transmission that drives the rear drive train. As long as you do not over load, shock or over speed the drivetrain there should be no problems driving at speed. I have done 80MPH on the freeway for hours in 4x crossing Wyoming in the aftermath of a blizzard.

The way to cause damage to the drivetrain is to operate in 4x when in good traction conditions - dry pavement for example - while turning. The front end and rear end tend to travel at slightly different velocities due to the geometry of the truck (front wheels truned) and the fact that the inside pair of wheels are experiencing a smaller radius curve and therefore turning more slowly than the outside pair of wheels. The problem is that the differentials are hard wired to the transfercase. The transfer case can not accommodate a difference in rotational speed between the front and rear outputs. The differences between front and rear end up as torque applied internal to the gear train in the Xfer case.

So as long as you are traveling straight ahead or have low enough traction to avoid over stressing the Xfer case, you can be in 4x.

Consider, "full time 4x" designs basically have a differential in the transfer case that accommodates different speeds between front and rear. But they also will provide much worse traction as all the power can be routed to the tire with the least traction.

 

^^^THIS!!! well said