Which is better, Part time or Full time?

[MoparNorm]

Well, with the possible exception of Selec-Trac Jeeps, 4x4s are either part or fulltime.....
JS

Ha!Ha!
I guess we were writing at the same time!

[AdventurerSport]

Yep, Norm, great minds think alike (or, at least, type at the same time, I guess...?) :)

'89-93 1st gen Cummins Dodge 4x4s came with solid front axles and locking hubs (No CAD). CAD came standard on all '94-up Dodge trucks, eliminating locking hubs. Locking hubs can still be had on Ford trucks, incidently...

As I say this, I realize it may not be true for all Cummins trucks in those years, but I've never seen a 1st gen Cummins with CAD, or without factory locking hubs...? And there are A LOT of 'em around here, (a few with, non-stock, FULLTIME 4wd...) :)

JS

[MoparNorm]

They must not offer the CAD on the Dana 70/80 then?

I missed the fact that his truck was a diesel, I was thinking about the CAD systems that went back to the early 80's.
There are a few 3rd Gen Cummins trucks around here without hubs, I'll have to crawl underneath one and check out the NP #....= )

[AdventurerSport]

CAD on Dana 70/80? Probably not...never seen one...new style Rams have fulltime front axles on 4x4s, no hubs, no CAD, nada...:)

JS

[KRB64]

Well, with the possible exception of Selec-Trac Jeeps, 4x4s are either part or fulltime.

With Selec-Trac, you get to choose, I had this feature on a '04 Liberty, and it worked very well. With Selec-Trac, you choose either 2wd, Part-Time 4wd (locked in), or Full-Time 4wd (power on demand, allows differential action while turning, so no binding). In 2Hi, there is no power put to the front axle at all, it's just there, much like any parttime 4wd, except no lockout hubs, so the driveshaft turns with the wheels. In parttime 4wd, it's locked in, with the front and rear driveshafts turning at the same speed, all the time, which can cause a bind in a turn or on dry pavement. In fulltime mode, it puts power to the front and rear, albeit at different speeds, so as to maintain positive traction at all four corners without binding, even in a turn. In low traction conditions, such as sand, snow or ice, it may be preferrable to lock in the 4wd. Just like NP203 equipped trucks. :)


Also, with NP203 fulltime 4wd, you have the advantage of using Hi OR Lo without LOC...I use this feature frequently. I can pull heavy wagons on pavement in LO without having to use LOC and still have excellent traction. Most Part-time 4wds only offer Low range in a Lock position, which doesn't work well at all on pavement...:) And, if you just put your truck in Low, and leave the lockouts dis-engaged, you're only pulling ever off the rear tires and that is problematic as well (wheel spin, low traction).

Make sense? :)

JS

Thats what I was getting at.

A partimer in HI is not the same as a full time in HI. A part time in HI will not handle as well as full time HI. They are only "equal" and comparable if the full time is in HI LOC. Or part time LOW and full time in LOW LOC right? So we are comparing apples and oranges not apples and apples.

So I guess what I was proposing was that we are comparing preferences of conveniene AND means of performance, not just two different means to the same end. They can not be considered a two way comparison but rather a three way?

Maybe I'm making this more complicated than necessary or missing the boat entirely? logic and method demonstration is not my strong suit!

Anyho, the auto disconnects that I'm familiar with (former rides:'89 Dakota & '90 gasser W250) were unreliable and always left you wondering was it REALLY engaged or not. Maybe the new Jeep stuff has eleminated all that now. I wouldn't know, my newest vehicle is a '92 straight axle and that suits my tech level and aspirations!

Bottom line is user preference and that is what the poll was wanting i guess. Full timers win!

[MoparNorm]

Thats what I was getting at.

A partimer in HI is not the same as a full time in HI. A part time in HI will not handle as well as full time HI. They are only "equal" and comparable if the full time is in HI LOC. Or part time LOW and full time in LOW LOC right? So we are comparing apples and oranges not apples and apples.....

The main difference is that the part time is a passive system, it splits the torque nearly evenly between front and rear 51/49. It cannot change from that mechanical setting and as such can't cope with hard surfaces or high traction surfaces without protest.

The full time is an active system and can be left in 4 wheel drive, "full time", it compensates for wheel slippage and transfers power to where it needs to be. Early full time systems may have been less capable, for some terrain or driving styles, but generally perform better in all types of 'general' low traction surfaces such as wet or icy roads.
Once shifted into low range the full time system works identically to a part time low range system, unless you have a newer NP242 transfer case which continues to act like a third "locker".
Which brings up the reality that ALL 4WD systems that are not equipped with a locking differential basically convert your ONE wheel drive vehicle to TWO wheel drive (one wheel on each axle).
The exceptions to this are the Jeep Quadra Drive II system which actually has three "lockers", one in each differential and one in the transfer case.
So, yeah, maybe you're making this harder than it needs to be, but you asked some valid questions...= )

Maybe the real question should be,
"Do you prefer selectable hubs or automatic systems and why"....

[JimmieD]

RE: CAD axles. Remember driving my '90 W-350 Ram, Norm? That has D-60 front, D-70 rear, part-time, locking hubs, NP205. There is no CAD vacuum disconnect.

Many CAD guys install the kits that revert to manual engagement as CAD is very failure prone with vacuum lines easily ripped off on trails. Problem is, in no-vacuum situations the axle goes into unlock, so if it took 4WD to get in you better hope you brought camping gear!

Most of us in snow country left the front hubs locked in for maybe 6 months. I do that on the Ram. Remember when we had the hauling to do on the hill, Norm, and you wondered if the front locking hubs were even working? They were, but they were already locked in before you chose 4-Lo or 4-Hi. Doesn't seem to do much harm if any to leave hubs locked in, but I'd unlock in summer up north.

I like fulltime 4WD. I like part-time 4WD. The ability to leave hubs locked in tames the argument of which is better, as the part-time becomes a virtual shift-at-will fulltime without getting out to lock the hubs in mud and snow, while also offering shift-at-will ability to be in 2WD [1WD].

[MoparNorm]

I didn't put it in 4WD that day. If it was in 4WD the front tires never spun, if fact if you remember, I found one hub turned "in" and one hub disengaged.
I suppose that the CAD was only used on 100 and 200 (150-250) trucks, with the Dana 44, but I have a 85 W350 front axle in my W200 and it was originally a CAD axle (but it has Dana 44 tubes so that answers that question).
Keeping the hubs turned all the time defeats the purpose of the hubs as far as wear and tear and fuel economy, so I suppose you'd be better off with a Fulltime system....= )

[AdventurerSport]

Yup, what he said....:) Keeping hubs locked in all the time kinda defeats the purpose of the hubs...yup. Fulltime RULES! :)

"hey, I work FULLTIME, why shouldn't my 4x4 do the same?" :P

JS...proud owner of many, many NP203 fulltime 4wd Dodge Power Wagons, since birth and beyond death (I plan to take my main truck WITH ME!). :)

[MoparNorm]

Yup, what he said....:) Keeping hubs locked in all the time kinda defeats the purpose of the hubs...yup. Fulltime RULES! :)

"hey, I work FULLTIME, why shouldn't my 4x4 do the same?" :P

JS...proud owner of many, many NP203 fulltime 4wd Dodge Power Wagons, since birth and beyond death (I plan to take my main truck WITH ME!). :)

Ha!Ha!
Just don't use the guys that burried the '57 Plymouth.....in that "waterproof" vault.....= )

[AdventurerSport]

Nope...thinking ABOVE ground vault, with regular checkups...:) And, a battery charger...just in case I come back to life...at least I'll have my fulltime 4wd Power Wagon! :)

JS

[JimmieD]

Now guys, are you really going to try to convince me that driving a Part-Time 4WD Dodge truck in 2-Hi with the hubs locked in is going to subject the drivetrain to the same wear and tear and parasitic drag as if it was fully engaged in 4 wheel drive!? Surely you wouldn't suggest that, now would you?

Not sure on the hubs that day, Norm, but they were supposed to already be locked in when you tried to lock one. Maybe it haywired itself...? However I do make mistakes, on VERY RARE occassions.... :~ )

[Gordon Maney]

Maybe I am the odd one here, but I don't very often need four wheel drive, other than winter. I might only use the front axle drive occasionally from November through March, and then maybe only 20% of that time.

Consequently, I like the idea of having lockouts for that greatest percentage of the time when I don't need assistance from the front axle. The lockouts allow all of those parts in the front to rest, not wear, and for better fuel economy. Also, I get a simpler and more easily repaired transfer case.

In the case of AdventurerSport where he has a farming operation continually requiring full capability, it makes sense to have the fulltime system.

[MoparNorm]

Now guys, are you really going to try to convince me that driving a Part-Time 4WD Dodge truck in 2-Hi with the hubs locked in is going to subject the drive train to the same wear and tear and parasitic drag as if it was fully engaged in 4 wheel drive!? Surely you wouldn't suggest that, now would you?....

YES!

Ha!ha! Here is what is happening in 2H, with your hubs unlocked:Tires rotate, hub is disconnected and nothing else in the front end is connected, so all moving parts are static and resting peacfully.....
Here is what happens in 2H with the hubs locked: Tires rotate, hubs rotate, knuckles turn, the axles turn, the differential turns, the driveline turns, the out-put shaft in the t-case turns, ONLY the collar gear that engages the chain is disengaged from the chain, it still rotates, EVERY moving part in that drive train STILL rotates, it needs lubrication, you have friction, bearing wear, rotating mass for the engine to push, so indeed the exact same parasitic drag and wear as when in 4WD....the only difference is the wear is on the "coast" side of the components and not the "load" side.
The engine may see some small fuel savings in effort, but the bearings get no rest.....= )

[MoparNorm]

Maybe I am the odd one here, but I don't very often need four wheel drive, other than winter. I might only use the front axle drive occasionally from November through March, and then maybe only 20% of that time.

Consequently, I like the idea of having lockouts for that greatest percentage of the time when I don't need assistance from the front axle. The lockouts allow all of those parts in the front to rest, not wear, and for better fuel economy. Also, I get a simpler and more easily repaired transfer case.

In the case of AdventurerSport where he has a farming operation continually requiring full capability, it makes sense to have the fulltime system.

OK, I'll admit it, I hate getting out of the cab in wet, cold weather, to romp in the mud, dig through ice and flail in the dark, to find the hubs, then repeat it all over again to retrieve my flashlight so I can see if my hubs are really engaged, then rock the vehicle, turn the wheel, and finally rip off a fingernail to eventually get the darn hubs to turn to fully engaged....then drive that 20%, get past the obstacle, wet pavement, snow or whatever, and repeat the process to disengage the hubs.
One winter it was too muddy, cold, wet, or insert reason here, to disengage the hubs, of course I forgot to do that until......the next time I needed 4WD.
With Full Time or automatic hubs, I can do all that from the comfort of the cab......and my shoes stay clean....= )
The fuel mileage difference is really negligible,... especially if you are driving around with the hubs always engaged like Mountain Boy or my forgetful self.....= )