the rumor of whether or not the engaging of the 4 wheel drive from 2H ONLY TO 4H at speeds 55 MPH and under will mess anything up or not. i am NOT talking about the electronic button, i am talking about the manual, on the floor shifter 4x4 engaging...
can i pull it into 4H at any speed under 55 as long as i let of the gas without it messing anything up???
can i put it back into 2h from 4h at any speed 55mph and under as well??
thanks

 

I do-no probs.

 

That makes 2 of us....although I haven't tried at 55. When ever I used it I was never over 40. In and out was on the fly.

 

I have put the truck in 4hi above 65 on occasion when the weather started to change on me in the winter. Some times I get a chuncking sound but not always.

 

If I have this right, your wanting to go into 4-Hi from 2-High at Hiway speeds.
When you do that, you strain a bunch of stuff that's not turning. You jerk it into high speed operation.
The Chain might stretch a little each time you do that. BUt if that Chain ever breaks at speed, you'll lose your whole transfer case. Not to mention the fact that you wont be moving the vehicle by it's own power from that moment on!

You can go back to 2-Hi any time.

 

Our commercial salesman at work has a 2003 f350 4x4, and he told me he engages the 4x4 at speeds of 100 mph, and he drives with it in 4x4 as fast as the truck can go! Wonder what the boss would say if he knew...

 

Now that I would have to see to beleive. The 4x4 systems were just not made to operate at those speeds. Besides..what the hell is he doing going 100 if he needs 4x4?

 

i wouldn't do it at 55....like billybob69 said....stretch, stretch SNAP........35 or under is what i'v always been told.....better safe than sorry


100 MPH into 4wheel high is STUPID.....even 65 is asking for it


stick with 35 and you'll be fine

 

In Alaska I engaged my hubs in October, put it into 4-hi and left it there till April.
On some really cold mornings the fronts would be a little stiff and the steering pretty tight and stubborn sometimes, but the slick conditions didn't strain anything.

But on dry pavment, shifting INTO 4-Hi could snap anything from the front spider's, u-joints to the transfer case itself.
Odd that a question like this would come up. What was the circumstance that prompted the question?

 

Well I've seen it and the reason he goes those speeds and does that is simple, hes an idiot and its a company truck so he doesnt care if he wrecks it!

 

Sheesh....wish I had a truck to play with and destroy and not have to pay for it...if that was the case....I would be looking at an F350, dually with a deisel. And just start hooking up to anything I could to see what I could pull! hehe

 

I usually drop down to about 35 mph before engaging the 4H. You can pop it back to 2H whenever. Doesn't the owner's manual say something about this?

Usually once I go into 4H the road clears up, and when I go back to 2H the ice and snow on the road returns. It's almost a law of nature....

 

If your truck is one that is covered in this forum, you can. These trucks have synchro mesh transfer cases. Nothing is stressed so long as you are not on dry pavement going around a corner. If you have an owners manual, it states that the transfer case can be shifted from 2 to 4 hi while driving under 55. That's why they're called Manual
shift on the FLY or MSOF, though only nutty salesmen shift while literally flying. Rob

 

My rule of thumb is if your truck's front axle is turning the same speed as the back ,you can engage any 4x4.If it has manual hubs than nothing is turning up front and would be a very rough shift if evan possible.If it has no hubs up front than you probably can.Anyone trying to engage into 4low at any speed other than zero is not thinking.You don't drive a standard at highway speed and drop into first gear.It won't want to go.gears are turning too fast.Same thing with the transfer case.I'm not sure thou how the f-150 engages the front diff or is it alway's turning?

 

My front diff doesn't have electronic or manual hubs. Always on. All I have is the transfer case lever on the floor.