Can someone tell me what is the maximum speed that I can drive after I engage the 4X4 on 4H and 4H low Range?
Also, is it normal for my F150 (4.6/ 78000 miles) to take some time for shifting gears on a cold morning?(32 dgrees)?

 

i was told your not supposed to do over 45 mph in the high range the low range is for torque mainly to get through messy conditions (mud and snow) or for pulling when u need power and traction

 

When I have used 4H I have driven at the speed limit around 60-65 and had no problem yet! Got 66K on it now. Haven't used 4L yet, other than just to play with it.

 

Ford recommends no more than 45-50mph. The front drivetrain components aren't balanced as good as the rear shaft/axle.

 

My manual states that you can shift into 4H at up to 55MPH. And states no max speed in 4. I usually slow to under 35 to shift in and have driven 60-65
with no problems in 145,000.
I've only used 4Low in mud at slow speeds

 

I have experienced the prob. but not on every cold morning. Matter of fact mine just did it two days ago