4x4 snow procedure

[lonestar]

Well we had our first big (6" lol for some) snow here in Kentucky and I have been playing with the my 4x4.

First off, what is the proper procedure for engaging auto hubs to minimize the risk of blowing them up. I have been slowing down to about 5mph or less, depressing clutch to minimize stress on drivetrain to allow for easier shifting and then slowly let out the clutch. Usually to go into 4low I come to complete stop.

I have noticed if i engage the 4x4 while parked or stopped then let out the clutch, the front drivetrain seems to slam or clunk into engaged postion. I assume this is normal, since the autohubs require some torque to engage?

I have been disengaging 4x4 when coming to a cleared road, but usually don't have the chance to back up 10 or so feet to disengage the hubs, fortunally they have not given any signs of engagment, such as binding, after disenaging.

How much addititional drivetrain noise should be expected? To me it just sounds like more road noise, like having nobby tires.

Now I know some of you are going to say go manual. I would like to, if I can find a manual tcase. I think its kinda dumb to have auto tcase and still have to get outside to lock the hubs. Besides, I have begun to like the auto hubs, being able to lock and unlock hubs according to road conditions with out getting my feet wet. I will go manual whenever these blow up. Hopefully they will last, since I don't do much heavy 4x4ing, just light mud, creekbeds and snow.

Thanks

Some might say, "use the search", but all I could find is usual posts about "4x4 not working".

 

[99explorer5.0]

Thats why i like my AWD. I dont need to worry about any of that crap.

 

[Byrd91]

You don't have to back up when you get to a cleared road. The hubs will still engage the axles, but the front and rear axles will be free from each other. All you will notice is the noise of the front axles moving, no binding or anything. This would be the same with manuals, you don't have to unlock them everytime you get to a paved road, just disengage the transfer case. I love having manual hubs with the pushbutton t-case because I can still shift on the fly if necessary if my hubs are already engaged, and I also have confidence that my 4x4 will work every time.

 

[VairKing]

Is there any damage in having manual hubs engaged while in 2wd for normal driving?

for example, i need 4x4 to get out of the driveway and to get to a major road, will it hurt if i continue to drive with the locked and in 2wd the remaining 55mph 10 mile drive to work/school?

 

[Sschultz]

VairKing,
It should be O.K. to drive with your hubs locked in while your in two wheel drive. However you don't want to be in four wheel drive without the hubs locked in.

 

[Alec]

Originally posted by lonestar
Now I know some of you are going to say go manual. I would like to, if I can find a manual tcase. I think its kinda dumb to have auto tcase and still have to get outside to lock the hubs. Besides, I have begun to like the auto hubs, being able to lock and unlock hubs according to road conditions with out getting my feet wet. I will go manual whenever these blow up. Hopefully they will last, since I don't do much heavy 4x4ing, just light mud, creekbeds and snow.

Thanks

Even with a manual tcase, you'd still have to get out to lock the hubs but could stay inside to engage the tcase, that's a crappy argument

But if your hubs give any sign of breaking, get the manuals. Until then, keep your feet dry

You might want to go ahead and buy the manual hubs just to have them. You'll need them eventually, and by having the manuals you can take them with you out on the trail as spares.

 

[lonestar]

Originally posted by Byrd91
The hubs will still engage the axles, but the front and rear axles will be free from each other. All you will notice is the noise of the front axles moving, no binding or anything. This would be the same with manuals, you don't have to unlock them everytime you get to a paved road, just disengage the transfer case.

I'm not sure about that. If there is LS in the front diff and both hubs are locked, there would be tremendous strain on the front drivetrain. Although most people have LS in the rear, there is not much worry because the rear doesn't do any turning, plus the rear axles are solid, (1st & 2nd gen), no U-joints at the wheels or the diff to worry about. Not sure what they due with LS in the newer independant rear.

Originally posted by Alec
Even with a manual tcase, you'd still have to get out to lock the hubs but could stay inside to engage the tcase, that's a crappy argument

NOt sure what your trying to say. I was stating that I really wouldn't want to go with manual hubs with a auto tcase, kinda defeats the purpose. Manual hubs would require me to get my feet wet regardless of the tcase. The only other option would be manual tcase with auto hubs, which makes more sense than vice versa.

 

[SteveVB]

Originally posted by lonestar
I'm not sure about that. If there is LS in the front diff and both hubs are locked, there would be tremendous strain on the front drivetrain. Although most people have LS in the rear, there is not much worry because the rear doesn't do any turning, plus the rear axles are solid, (1st & 2nd gen), no U-joints at the wheels or the diff to worry about. Not sure what they due with LS in the newer independant rear.



NOt sure what your trying to say. I was stating that I really wouldn't want to go with manual hubs with a auto tcase, kinda defeats the purpose. Manual hubs would require me to get my feet wet regardless of the tcase. The only other option would be manual tcase with auto hubs, which makes more sense than vice versa.

Byrd 91 is right the front and rear axles are disconnected, the front axle is just turning no limited slips inthe front- unless you addded one.
With the push button trans case you just lock the manual hubs once and shift in and out as you need 4wd. Same idea as letting the auto hubs engage and not backing up everytime you switch out of 4wd. Just push the button each time you want 4wd. - the only time I made sure I disengaged the auto hubs was at the end of the day, or if I was going to be parked for a while- concerned they would freeze in position- basis for this -NONE, although I have had manuals freeze in position. Reversing to unlock the hubs each time is more PITA than turning the manual hubs a couple of times.

Running with the front axle engaged is of no concern- minimal additional wear. Take a look at any late model 4wd they all spin the axles all the time.

FYI-You dont have an auto transfercase- you have a push button shifted transfercase - auto cases have clutches and such in the case to transfer power- your case basically the shifter is a button rather than a handle - thats it.

The front axle has no limited slip from the factory so no added strain to the front unless you added one. The total amount of time you are in 4wd if you use it on snow in most places (ex northern US) wont add any significant wear to the front axle componants.
BTW- Even though the rears dont have a pivot to turn, the wheels each have their own speed around corners adding the stresses you allude, and cause wear to the the trac-lok.

Remember late models 4xs dont even have hubs they have a single disconnect in the axle someplace - so the u-joints and diffs all spin all the time. Early Jeeps and most 4wd trucks didnt come with any way to disconnect the front wheels from the axles. Until the auto manufacturers saw the great demand for "locking hubs" from the aftermarket did they begin to offer them on their fourwheel drive vehicles.

Have Fun and just push the button when you need it(actually BEFORE you need it),

 

[lonestar]

Originally posted by SteveVB
Byrd 91 is right the front and rear axles are disconnected, the front axle is just turning no limited slips inthe front- unless you addded one.

Not 100% sure, but I know when a test drove it, I wanted to make sure the the 4x4 wouid engage, so I pushd the button listening for it to engage. When I began to enter a turn I began to hear binding in the drivetrain and get wheel hop. So I immediatly hit the clutch and came to a stop (no coasting due to binding in drivetrain), and disengaged it. I have never experience this in a 4x4 with an open front diff. Then I read in the owners manual about the warnings about having a LS in the front, so assumed it came factory, kinda surprised.

Originally posted by SteveVB
Running with the front axle engaged is of no concern- minimal additional wear. Take a look at any late model 4wd they all spin the axles all the time.

Is it even possible to run a LS in the front on these models. I don't see how, or on the AWD either.

Originally posted by SteveVB
FYI-You dont have an auto transfercase- you have a push button shifted transfercase - auto cases have clutches and such in the case to transfer power- your case basically the shifter is a button rather than a handle - thats it.

I believe when the push-button was first introduced it was refered to as an auto tcase. Now they have the AWD, auto engaging 4wd and the 60/40 power split computer controlled tcases. I still refer to push-button as auto, basically a businessman's (lazy) 4wd.

 

[SteveVB]

Any 4wd will hip and skip and bind on a hard surface. tried it? Every 4wd I have ever owned/driven- about 20 will complain on hard surfaces. The front axle( the whole drivetrain really) needs some slipage or drivetrain binding will occur- the whole reason to turn off the 4wd when you get to hard surfaces. remember that ALL 4 wheels travel a different distance when you turn so the slack has to be taken up someplace- usually a wheel slipping- if they cant slip something else has to give- if your lucky a chirp from a tire- if not ... a u-joint or worse. On a hard dry surface nothing can slip so the drivetrain binds up.
NO manufacturer will put a non-selectable L/S in a front axle - they would have legal fees out the wazoo after the first snow. The LS would provide no directional control and they would be sued since they know it. LS has never been offered in the front axle.

Sure you can run a LS in the front on a late model- whether they make one or not thats the only question.

I never remember hearing auto anything(its been 12 years! so it may not mean much) , but they were selling the "touch- drive" fourwheel drive. Makes it sound automatic doesnt it

Good Luck

 

[Robert]

A limited slip would have no bearing on whether or not the front hubs were locked or not. The rear does turn as well. It actually has a harder job of turning since the wheels can't point in the intended direction like the front wheels do. There is more of a speed difference between the two rear wheels when turning than there is between the two front wheels. The whole purpose of a limited slip is just that, to provide traction yet still be able to slip a limited amount. The difference in torque allowed before the wheels slip between the wheels on a limited slip axle is pretty low. Once the torque difference exceeds the limited slips capability the two wheels will slip with regards to each other. Turning is one such instance. The reason a 4x4 hops when going around turns on a hard surface is due to the front and rear axles being locked together not because of a limited slip with the hubs being locked. Now if you add a true locker to the front and have your hubs locked turning would be very difficult. This is one reason why people with lockers in the front will unlock one of their hubs so that they can still turn. A limited slip doesn't lock the two wheels together like a locker does.

 

[MuddLover]

Well said

Well said Robert!

There seems to be a lot of confusion here about open diffs, limited slip, solid axles, and lockers.

It appears that most care confusing a limited slip rear with an SRA, not the case. A limited slip differential allows one wheel to carry the vehicle until a slip is recognised then both wheels will turn together to a limited extent yet still allowing for uneven terrain and turning curves.

A solid rear axle is just that, solid, it is one piece unlike the two half shafts of a LS set up. A SRA would be entirely unsafe on paved surfaces and would even give some wheel hop on hardpack due to the fact that whether you are driving straight, making a turn, or climbing off camber both rear wheels will turn at the same speed and can do nothing else without wheel hop or something breaking.

Open differentials are most common in front ends for ease of steering as well as safety precautions. An open diff is much like a LS in that it utilizes two half shafts, however an open doesn't attempt to displace the power to both wheels in a slip situation it simply shunts all power to the wheel which is not binding. So if you are mudding or rock crawling and put a front wheel in the air you will basically be back to a rear wheel drive since just about all of the power on the front will be transferred to the free wheel.

A locker wheter it be front or rear basically turns a limited or open differential into a solid axle by use of pneumatic or hydraulic clutches, this leaves that axle nearly impossible to steer due to the fact that both tires turn at exactly the same speed with no reguard for terrain or traction.

To understand the binding sensation that is felt in turns one must first realize that when in 4x4 both the front and rear will turn at the same speed yet the rear tires must travel farther in a turn thus binding up the drivelines and causing a hop or possibly a slip that the differentials can make up for.

HTH

 

[Byrd91]

Robert and Steve are both correct in what they are saying. I will also add with regard to:

I have never experience this in a 4x4 with an open front diff

This is not true Lonestar. If you were driving any real 4WD vehicle (not AWD or auto 4WD or any of the other new technology traction systems) on dry pavement, while turning you would get binding. Just like Steve said about all 20 of his 4x4s, they will complain on hard dry, high traction surfaces.

 

[lonestar]

Re: Well said

Originally posted by MuddLover
There seems to be a lot of confusion here about open diffs, limited slip, solid axles, and lockers.

I understand the difference. I have looked into purchasing a PowerTrax (which is basically a L/S locker, meaning it disengages in turns) and/or rebuilding my Trac-loc. When I'm thinking of a true locker I think of a ARB (no slipping until the locker is disengaged, virtually a solid axle.)

Originally posted by MuddLover
A limited slip differential allows one wheel to carry the vehicle until a slip is recognised then both wheels will turn together to a limited extent yet still allowing for uneven terrain and turning curves.

Not exactly, the clutch pack in the L/s is engaged all the time, meaning both wheels drive all the time. When cornering the the clutches slip allowing one wheel to travel farther. I believe the L/S is only capable of transfering a max of 90 ft-lbs differential torque betwwen the wheels. So if one wheel is loose and it requires more than 90 ft-lb of torque to move, the loose wheel will spin like an open diff.



I think the confusion began when I refered to the rear as having a solid axle, meaning no independant susp. and having solid shafts from the diff to the wheel, not requiring U-joints in the half shafts. I didn't mean solid from one wheel to the other.

NOw about the post stating there was no need to unlock the front hubs. Assuming I had a L/S in the front, I was wondering about the stress in the u-joints in the front half shafts.

Now that I think about it, I guess the front drivetrain could be binding through the tcase to the rear. I could swear that both front tires spin though. Why would they put any front L/S warnings in the owners manual if it wasn't offered from the factory. It does state not to engage 4x4 on dry pavement, that would cover any lawsuits.

 

[Byrd91]

Now that I think about it, I guess the front drivetrain could be binding through the tcase to the rear. I could swear that both front tires spin though. Why would they put any front L/S warnings in the owners manual if it wasn't offered from the factory. It does state not to engage 4x4 on dry pavement, that would cover any lawsuits.

Lonestar, I think you answered you own question earlier in the post. The fact that both wheels are spinning does not necessarily mean that you have an LSD. It just means that both wheels are feeling close to the same amount of traction and therefore resistance torque. With a limited slip the "close to the same" increases due to limited slip action. Thats why if both tires are on ice, mud, or even pavement, you can often break them both loose (ok, pavement maybe far fetched for us with 160HP) given the right situation like even weight distribution and such. It might even help to think about it this way, when you are just driving down the road are your wheels spinning at the same speed because they are locked together....no, they're spinning at the same speed because the traction is equal and the differential is spreading the torque evenly.

To sum it up... yes, the binding is coming from the fact that when you turn, the sum speed of the front 2 wheels does not equal that of the rear 2 wheels(and therefore the front driveshaft speed doesn't equal the rear driveshaft speed) and the transfercase does not like that.

I hope this did an ok job of clearing up some more confusion.

 

[SteveVB]

Re: Re: Well said

Originally posted by lonestar

NOw about the post stating there was no need to unlock the front hubs. Assuming I had a L/S in the front, I was wondering about the stress in the u-joints in the front half shafts.

Lonestar ,
Assuming you have a front L/S- which I doubt unless it was aftermarket, the stresses would be marginally greater with the L/S - but like you said the stock L/S is easily overpowered (unless you "tighten it up") , and the stresses would be the same as if it were in 4 wheel drive, and the parts are designed for the stresses of being in 4wd.

You still dont sound like you believe that you dont have a L/S in the front axle. Jack up the front axle turn either wheel, if other one turns the opposite direction- open diff, if they turn the same direction then it is L/S.

I dont remember anything in the 91 manual about a LS in the front, but its interesting, Ill have to go look.


Muddlover you have the L/S action backward- like Lonestar said the clutches/mechanism are engaged and the axles "locked" until they are overpowered by the differing wheel speeds. Non- selectable lockers (No-Slip,Detroit others) work the same way- just no clutches teeth and grooves usually.

 

[MuddLover]

re: limited slip

I quite possibly am wrong on the way a limited slip is supposed to work, I am not exactly an expert on the internals. My descriptions of the drive systems were simply from what I have seen and experienced while wheeling. One situation that led me to my uderstanding was that when you are in a freewheel type situation you can apply minimal brake pressure and the axle will lock back down.

 

[lonestar]

Thanks Steve for clearing things up..

Originally posted by MuddLover
I quite possibly am wrong on the way a limited slip is supposed to work, I am not exactly an expert on the internals.

Not trying to be rude, but why such the long post trying to explain something you didn't understand and in turn creating a confusion that was never there.

Originally posted by MuddLover
I when you are in a freewheel type situation you can apply minimal brake pressure and the axle will lock back down

This is due to the even braking action between the wheels. If one wheel is slipping or free, the applied drag from the brakes equalizes the resistance between the wheels and brings the diifferential torque closer to the 90 ft-lb differential break torque, allowing the L/S to lock, causing both wheels to turn and regain traction.

 

[Robert]

Ford's minimum breakaway torque requirements for the the Traction-Lok axle is 20 ft/lbs. not 90 ft/lbs. I couldn't find a reference as to how high it could be, but as long as it is at least 20 ft/lbs. it is working properly according to Ford. Here is the Ford procedure for testing proper operation:

"Use a torque wrench with the capacity of at least 271 Nm (200 ft lbs) to rotate the axle shaft. Be sure that the transmission is in NEUTRAL, and that one rear wheel is on the floor and the other rear wheel is raised off the floor. The breakaway torque required to start rotation should be at least 27 Nm (20 ft lbs). The initial breakaway torque may be higher than the continuous turning torque."

 

[MuddLover]

Excuse me!

Originally posted by lonestar

Not trying to be rude, but why such the long post trying to explain something you didn't understand and in turn creating a confusion that was never there.

Well excuse the hell out of me!!! At least I tried to appologize for my mistake instead of attacking another member's post after my error was pointed out.