so yesterday i had a late christmas with my friend (the one whose jeep started the whole thing last november...), but anyways, i now have 2 sets of wrenches, a 10-pc socket wrench set, one set of 5 ea phillips and flathead screwdrivers, and a nice husky toolbag to keep it all in

also finally finished skimming through the ford service manuals my other friend loaned me, which was some interesting reading...when i dug them out from under my zils and knitting projects lol. seriously, i want my own set now!

back to the point, the section in the manual answered a few of my questions about why 4x4 on pavement is a no-no...i get the windup thing, but what i don't get is how one set of tires covers a different distance than the others??

interestingly enough, there was a little box on disengaging 4wd that mentioned "extreme cold" can delay/prevent shifting back to 2H even if 4wd light goes out. also noted that even backing up may not solve that. doesn't fix anything but makes me feel better knowing it. my friend laughed when i told him about the cold thing- he's from ny and didn't consider 25* cold. i say it could be for a southern truck built in ky- (and her bday is in exactly three weeks lol)!

studied up on my t-case too...i like pictures so i liked the power flow diagrams, but i couldn't for the life of me see any difference between the 4H and 4L pix. *shrugs*

new tools plus a little more knowledge than yesterday and temps above freezing was sufficient motivation to go outside to mess around with her some...shoot, was even going to do routine fluid check and stuff on my honda too!

...cue the rain...grrrr!

 

also noticed ford says keeping manual hubs in locked position is ok...i've heard people adamantly insist that it's not good for my truck to leave them on lock and others just as confidently assure me that it's fine. so what gives??

 

good question on the hubs?!? i thought it was a no-no most of the time.

 

At the front of the T-Case there is a planetary set. The input gear is hooked to the sun gear. The ring on the outside is fixed into the case. The cage that holds the planetary then moves around at a slower speed.

The output shaft is independent from the input shaft - there's a bearing in between them. There is a collar on the shaft that can either slide forward to engage the input shaft, locking everything together for high range, or it can be slid back and then the output shaft is connected to the cage that moves around slower.

I never did understand why they didn't make them like automatic tranny planetary sets. In an automatic, the gears don't move relative to each other when in 1:1 ratio. No wear, and no drag burning up fuel. It's all a matter of how the clutches are arraigned.

 

Hurt it? No. Wear things out faster? Yes.
When the hubs are out and the T-case is in 2H, the front is totally disengaged. Due to drag in the hubs and the T-case shifter, the parts will windmill slowly. You can see this on jacked up trucks where the drive shaft is easily seen - notice how the front drive shaft keeps rolling down after they stop? Because the parts are rolling slow, they wear out less fast. Plus the truck burns less fuel.

 

my truck will not spin the shafts when the case/hubs are disengaged.

the other thing with leaving the hubs locked is that it burns more fuel and eats horsepower. thats alot of extra parts to make move along with getting a 7k truck rolling.

 

Leaving your hubs locked in will turn everything back to the t-case.
It will wear things out, but will not hurt anything as long as they are in spec. AKA, differential full of fluid! :P

4wd on pavement isn't a big deal as long as your gear ratio's are the same, and your tires are inflated properly, and not 2 different sizes.
It's not a needed thing, so you should take it out of 4 wheel drive, even if you just leave the hubs locked in.
Its a lot tougher on stoping and stuff in an auto especially while in 4wd, cause you have to stop the engine with the front tires as well as the back, cause they are in sync, so its tougher on the powertrain, cause front does more then 60% of the braking of the truck.
So in theory, stoping on dry pavement in 4wd is bad.
However, they make countless 4wd cars that are all time 4wd. this should tell you that its not a big deal.
They are generally 4 wheel disk though as well.

As for the T-case disengaging. there are forks that push the gear out, so you shouldn't be engaged if you disengage the lever. On a push button t-case, this is however true, it might not pop out right away.
And the same for chevy's. they don't always disengage right away. I know mine does right away at 55 in cold temps. So that sounds like a load of crap to me.
Perhaps certain ones do not, but the one in your truck should.
The only way it wouldn't disengage is if your shift fork or mode forks were screwed up bad enough to not pop it out.
Like i had told ya before. have somebody watch the T-case and see if the knuckle rotates while you slowly move forward. This will tell you if its stuck in 4high.


As for the clutch setup and all that in the t-case. the only guess i have is. clutches slip, so that's bad. And all the other stuff would change the size as well.

 

the only time its bad to be on pavement in 4wd is turning, straight lines wont hurt and neither will braking. turnign is hard on u-joints and axles because the outer wheel and inner wheel trac at different speeds, same principle as a rear axle with a locker making a turn and chirping one tire. just times 4. so imagine the stress you are putting the frotn axle through when you cut the wheel with it locked in, its even worse then the stress of a locker in the rear. thats also why you feel the pops and squeals from the fornt end if you do have the axles engaged in 4wd and make the turns, it doesnt even have to be on pavement, hard packed dirt will yield similar effects, the key is having a surface that will "give" and let the wheels do what they need to and stay unloaded. the binding is what will break joints and scatter diffs.
our trucks have no clutches in the t-case, its either in or out via a shift fork and a big assssss chain. 4 low is achieved through a planetary set as mentinoned above working on the similar principle of an auto tranny planetary gearset, thats why the pictures in the book look almost the same, depending on what gets held and what spins determines where the power goes. its been a long time since i had a t-case apart but they are all very similar in function.

the full time 4wd vehicles are different then the system in our trucks, while they are all wheel drive they are not locked in the same way our trucks are. if they were then they would scatter parts. they are either clutched in some way to allow slippage on turns or they are a 2wd system with an auto function to enable power to wheels when loss of traction occurs.

 

spline clutch

 

i dont recall there being a spline clutch in a 4407?

 

http://www.4x4abc.com/4WD101/driveline-bind.html

 

what about the 1356 though? i *thought* that was my truck had...now i wanna go crawl underneath and look, but it's dark

 

I don't recall there being a spline clutch in any of our available T-Cases.

The 1356 is what I have. AKA t-15?....
That is the lighter duty T-Case.
4407 I thought was on the 250's and up.

I'm not sure on this kinda info though.

 

4407 became standard in the 97's others could have gone either way, 1356 is the light duty, 4407 is the heavy duty, neither have a spline clutch in them, thats why they are not shift on the fly t-case's. they have auto hubs that wratchet when engaged and manual hubs that have to be stopped to engage.

 

what do you mean not shift on the fly?

Thats a chevy you can't shift while moving, not an OBS ford.

I know i can't shift while moving with the 02 though. it wont engage. different setup.