[QUOTE=dirtydog;3116194]How would Chrysler know you were doing The ONLY reason they consider it "Part Time" is because it cant be used on dry pavement due to binding. That is the only reason.
QUOTE]

With the transfer case engaged in 4Hi it is not part time 4wd it is fully engaged. The only Ram trucks that have a part time 4wd are those that are equipped with the 4WD auto.

 

You don't understand what part time 4wd means.
Part time 4wd = no center differential or viscous coupler - front and rear driveshaft's must turn at exactly the same rate.

Full time 4wd (AWD) = center diff or viscous coupler which allows the front and rear shafts to turn at different rates and not bind the drivetrain.

Auto 4wd is an engagement system that turns the 4wd system on.

 

I do know the difference but thanks. I just think you misunderstood what I was saying. When I said there is no difference, I was talking about the front differential being the same. Please re-read and you'll see what I meant. Maybe I wasnt clear but I knew what i meant..lol I tried to make it simple for OP without going all technical.
I made it simple by saying...as long as their is slip on the road(which acts like the center differential) then there is no bind and all is good. Yes, I understand there is a difference, but the road slip allows everything to be smooth and have much less stress if any at all.


Incorrect. read oldjeep above.

My 2000 Silverado had Auto 4wd selection which would detect wheel slip and engage automatically. It was still a Part-time system because it did not have a center diff.
There are AWD Rams though with a center diff.

Forget all that. OP was on Snow covered roads. There should not have been any kind of failure, even at the speed he was travelling at. I suppose if the roads were iffy and he was hitting alot of bare patches. That would put pressure on the diffs and cause pressure in them(heat)

 

The quote got messed up - I was responding to the other guy

 

Or his tires are inflated at slightly different pressures, worn down more in the back than the front causing a smaller diameter or the 3.55's are actually 3.55 in the rear and 3.54 in the front (pretty common that ratios don't exactly match)

 

haha. I was actually gonna ask if that was the case that but I decided not to. I assumed

Very true on the tires.

If Dodge doesn't have a strict tolerance of their gears and they are original, I'd gave to say its on them. As far as I know, most of the domestic truck makers use AAM, Motive..etc all known reputable companies.

It was a COMPANY truck. I think they treat Fleet vehicles different? Don't they?

 

Apparently I should have stopped when I was ahead...I just reread my last post and realized I was wrong. In the first sentence I said part time 4wd and meant all-wheel drive which is not an option on Ram trucks (of course you already knew that!).

In my original post I said it correctly in that 4wd auto is controlled when the computer detects slippage. The 4wd auto feature on these trucks is an optional feature, without it you have 3 settings on the selector switch 2wd, 4wd lock and 4wd low. The original poster also said 4HI not 4wd auto which I would assume means that his truck has the same transfer case option as mine.

 

The diffs have nothing to do with it, and I do see a problem with driving hwy speeds engaged. If you can do 60-70 then your tires are not slipping, otherwise you'd be in a ditch.

I would agree and lean towards mechanical failure if it was just going down the hwy, but was that the only time it was placed in 4wd or has it been engaged for much longer and hwy driving was just part of the time?

Also, every 4wd Ram is considered a "Part-time" system. They do not make a "full-time".

 

I'm with dirtydog on the front diff being no different than the rear one. The front diff is open so the stress of 4WD is mostly on the transfer case gears. Besides, the OP said the truck was being driven on a straight road with snowy conditions. That and the fact that plenty of folks on this forum have had pinion bearing issues with the rear axles, I would think this was a mechanical failure of the front diff. Also my manual only puts a speed limit on 4WD Low, it's silent on the 4WD High, but it warns that at any speed, 4WD should only be used under slippery conditions. The failure mechanism of the OP sure sounds a lot like the rear failures, the pinion nut loosens, the bearing fails, the gear gets sucked into the axle and everything explodes with the drive shaft breaking off and damaging things around it.

 

Pretty sure that he said the pinion snapped - which would be a stress failure not a nut falling off.

Given his initial description and how I've seen failures like this in the past - I'd guess that the tcase cracked first, which caused the pinion to break off.