I have a 2004.5 ram diesel 4X4 2500. The manual says dont drive in 4X4 over 80 km/h. Is this true or does this mean dont shift in or out past 80? I know all our driveline componenets turn anyways on our trucks so would it hurt to drive in 4X4 at 100 km/hour?

 

Well 4wd shouldn't be engaged on the pavement unless the conditions make it slippery. If your using it in dry conditions the drive line will bind and you're going to start busting parts. As for driving over 80km/h part of that probably has to do with the oil not being able to cool fast enough.

 

i drive most of my trucks in 4X4 all the time in the winter. almost for 3-4 months at a time. only time i take it out is when im in a parking lot. i never had a problem but i definetly keep up with my fluid changes

 

Don't know where you are but you list a sled, so I'm guessing snow counry. I drive mine, and every 4x4 I've ever owned, in 4hi at highway speed regularily when conditions warrant it. Shift when needed, safety first! But I usually shift at lower speed, about 80-90 kmh. I've always unloaded the drivetrain 1st, neutral or cutch. Never had a hint of a problem and my GMC has almost 300,000Km on it, the CTD has 110,000km.

Cya

 

in the summer- i will engage the 4x4 on a straight road for a couple of miles to lube everything up ( i have dyna-trac locking hubs) going 45mph for 10 minutes in 4x4 on a straight dry road is doing no damage-nothing is binding. if you are in 4x4 trying to turn or traveling at excessive speeds-then there is the potential for binding/damage.

 

I use 4HI all the time on slick roads. That's part of the reason I pay extra to have a 4wd.

Nick

 

I sometimes have to kick it into 4 hi to get rolling, but before I shift to third Im back in 2 wheel. I dont like the feeling of front wheels turning while Im driving. Handles wierd I think, 2 rear axles with both lockers and the power divider locked....Now thats they way to go. lol

 

why does it cause binding on dry surfaces? are the 2 diff ratios different?

 

Front and rear tires travel different distances in turns, binding up driveline.

 

I've driven hundreds of miles at a time in on intermittent slick and dry roads in 4 hi at 45-65mph with no ill-effects, not even much of a drop in mpg.

Just take it out of 4wd when turning tight on dry pavement.

 

I had an International Scout 4x4 years ago and the manual stated not to use 4x4 on dry surfaces. Shop foreman said the front and rear diff. would try to compete and torque up the drive line causing diff. and/or trans problems. My '03 dually is 2-wheel drive with anti-slip diff. No 4x4 problems.

 

I use 4x4 often when it is slick out at Highway speeds... Always have.

I do usually engage it at a low speed though 30 mph probably.

 

In dry conditions your tires have max traction when you turn with 4wd on or even going in a straight line the two diffs will have different speeds and usually will transfered that to the t-case or the tranny. The diffs need to be going the same speed to not cause problems. When your in the snow/ice or off the pavement It is ok to engage the 4wd. The reason is that the tires don't have max traction on those surfaces so if one diff is going fast/slower then the other a tire will be able to break its traction from the surface to match the speed of the other diff.

An AWD case is able to go on dry pavement because it has a clutch in the t-case to allow the drive shafts to catch up to one another if they end up binding.

 

I would be afraid to run it on dry pavement. There was a post along with pictures on here a year or so ago showing a busted transfer case. The original poster asked the question "What caused this?". There were tons of answers, he jumped the truck, too much power, etc... turns out the answer was a fairly stock truck ran on dry pavement in four wheel drive!

The small differences in the travel of the front and rear wheels bind up the driveline and can cause carnage. With the front tires being more compressed under the weight of the engine the effective radius of the front tires is smaller than the rears. Thats enough cause problems even in a straight line if enough traction is present.

 

Take a look at all the racers. If it's Ok to drive down the track WOT throttle up to 125 MPH, I think you'll be alright at 65 MPH. I drive mine in 4 HI all the time because the roads are plain nasty right now.