Is it ok to leave front driveshaft off a AWD???

[williams.cory]

My front driveshaft is completely shot. So I took it off to make sure thats what it was. Sure enough it was. But I was wondering if it is ok to leave the d/s off on a AWD? If you do, won't it burn up the viscous coupling? I already know about the park not working with it, but i want to be sure if it is ok to leave off.

 

[Turdle]

I am still not convinced it is healthy for the transfer case. I'd try to locate a shaft as soon as you can afford one.

 

[techieman33]

You should be ok for a short time, just remember to use the emergency brake every time you park or it will roll away

 

[rhyno]

I ran without one for about two years and didnt have a problem. My transfer case was stuck in 4x4 so i removed the front shaft.

 

[techieman33]

I ran without one for about two years and didnt have a problem. My transfer case was stuck in 4x4 so i removed the front shaft.

Not the same thing, he has a v8 with the awd transfer case

 

[williams.cory]

I think I will have to run without it for a short time. Only thing is, I just discovered yesterday that my e-brake doesnt work Another project to fix......lol

 

[CHEESYPOOFS]

you should just get it converted to all the time 2wd ^_^

 

[williams.cory]

How do I convert it????

 

[CHEESYPOOFS]

now that im not sure but i do know its possible

 

[gavin]

there's no definitive answer as to wether or not driving without the front shaft will destroy the viscous coupling.
most people say yes, it will.

I'm not convinced that it will.

But there has been no testing (to my knowledge) to give a definitive answer.

I've driven months, and a few thousand miles, without my front shaft, and my VC still appears to be good.

As for converting to 2wd, you should just need to replace the tailshaft of the transmission with one from a 2wd 4R70W (or the whole transmission needs to be replaced with a 2WD unit). But that will still leave the front diff in place, obviously.

 

[gijoecam]

Fact: Driving without the front driveshaft will cause the VC to slip all the time.
Fact: Ford does not recommend driving with different sized tires because it forces the VC to slip, and can damage the VC.

The next logical step would be that driving without the front driveshaft can damage the VC (Isn't that the transitive reasoning?). Sounds logical to me... but it's your vehicle. Do as you see fit.

-Joe

 

[williams.cory]

I really dont want to drive around without it, believe me! But i kinda have to. I'm broke

 

[ericautopart]

it's going to cost you more than a driveshaft if you wait...

 

[gavin]

Fact: Driving without the front driveshaft will cause the VC to slip all the time.
Fact: Ford does not recommend driving with different sized tires because it forces the VC to slip, and can damage the VC.

The next logical step would be that driving without the front driveshaft can damage the VC (Isn't that the transitive reasoning?). Sounds logical to me... but it's your vehicle. Do as you see fit.

-Joe

slippage in the VC is mainly caused when the rear tires are spinning faster than the front, with the front driveline slowing the front output.
with no tension on the front output, it's free to spin as fast as the rear

but... this is just the reasoning I've came up with... and yes, I know I could be wrong

 

[gijoecam]

slippage in the VC is mainly caused when the rear tires are spinning faster than the front, with the front driveline slowing the front output.
with no tension on the front output, it's free to spin as fast as the rear

but... this is just the reasoning I've came up with... and yes, I know I could be wrong

If you're agreeing with me, then yes, you are correct... ... But only partly.

With no resistance from the front driveshaft, the front output is free to rotate faster than the rear output, limited in relative speed by the VC...

If it makes it easier to understand, think of a solid axle mounted in the middle of the truck between the front and rear driveshafts... If you break an axle shaft, the broken side output from the diff is free to rotate to whatever extent the differential lets it. In the case of the VC, it limits the amount of slippage on the 'broken' side... to an extent...

The inner workings of the VC were hashed-out a little more in this thread:
http://www.explorerforum.com/forums/showthread.php?t=225515

Hope that helps.

 

[gavin]

If you're agreeing with me, then yes, you are correct... ... But only partly.

With no resistance from the front driveshaft, the front output is free to rotate faster than the rear output, limited in relative speed by the VC...

If it makes it easier to understand, think of a solid axle mounted in the middle of the truck between the front and rear driveshafts... If you break an axle shaft, the broken side output from the diff is free to rotate to whatever extent the differential lets it. In the case of the VC, it limits the amount of slippage on the 'broken' side... to an extent...

The inner workings of the VC were hashed-out a little more in this thread:
http://www.explorerforum.com/forums/showthread.php?t=225515

Hope that helps.

you know... I don't know wether or not I was agreeing. I believe only partly, haha.

Since the front output is fed by the chain, which is connected to the input via the VC, I don't see how the front can spin faster than the rear. Now, if it can, then yes, I agree that it will destroy the VC.
But the rear output is "more connected" than the front output.

Then again... I do now remember that when I had my front shaft out, truck in gear, but blocked by 2x4's, the front output was still spinning. So I could definately see power braking, or very quick acceleration, destroy the VC.

Under normal, conservative driving, I do not believe it would cause too much harm.

But, for all I know, those few thousand miles without a front shaft in my truck, caused my VC to go bad, which is causing this PITA vibrations I've had for well over a year.

Although the AWD traction is still there, and it doesn't seem like my VC has frozen/seized, due to still being able to get the rear tires to spin without the front spinning (first very icey day of winter a few weeks back).

 

[gijoecam]

you know... I don't know wether or not I was agreeing. I believe only partly, haha.

Since the front output is fed by the chain, which is connected to the input via the VC, I don't see how the front can spin faster than the rear. Now, if it can, then yes, I agree that it will destroy the VC.
But the rear output is "more connected" than the front output.

As with a differential, power will take the path of least resistance when it can. Remove the VC from the equation, and the truck won't move at all; it'll just spin the front output shaft. The VC serves to limit the amount of freedom the front output has by linking it to the rear output. It's a really clever design IMHO... But I digress...

The rear output is not a direct-drive on the AWD case. The input drives the planetary gears, which in turn drives the sun gear (connected to the front output) and the ring gear (connected to the rear output). In the 44-05 Auto-4wd cases, the front output drives the rear output directly, and the clutch coil 'grabs' that shaft as necessary, linking the front and rear outputs. They function completely different... THe bottom line is that removing the front shaft in an AWD case can and does allow the VC to turn. **Not freely**, but turn none the less. The VC is what limits that movement.

Here's an experiment to try: With the front shaft out, mark the output flanges. Get in the truck, start it up, put it in gear, and brake torque the engine for, say, 15 seconds. Do not let the rear wheels spin, just put pressure on the driveline. If the VC is working properly (i.e. not siezed) the two outputs will no longer be lined-up.

Then again... I do now remember that when I had my front shaft out, truck in gear, but blocked by 2x4's, the front output was still spinning. So I could definately see power braking, or very quick acceleration, destroy the VC.

Exactly as I described. Were it not for the VC, it would allow the front output to freewheel... just like one rear wheel of a 2wd truck spinning on ice.

Under normal, conservative driving, I do not believe it would cause too much harm.

It's your t-case,,, do as you see fit. But Ford obviously didn't want it to see sustained slippage... That's why they clearly state not to run a different sized spare on the AWD case, even in a pinch.

But, for all I know, those few thousand miles without a front shaft in my truck, caused my VC to go bad, which is causing this PITA vibrations I've had for well over a year.

Although the AWD traction is still there, and it doesn't seem like my VC has frozen/seized, due to still being able to get the rear tires to spin without the front spinning (first very icey day of winter a few weeks back).

That's where I'd put my money... VC's are a funny beast... I'd love to get my hands on one and see what makes it tick!

 

[jls1znv9999]

I talked with several mechanics that work for Ford. The only reason that say not to drive without it is due to the fact that the brake system is 65% rear and 35% in the front. Without the prop shaft (front drive shaft) it will not stay were you park it. It's just a concern about other drivers. The only thing you might notice is that you will have to lift the front end and turn the front tires to get the bolts to match up.

 

[gijoecam]

I talked with several mechanics that work for Ford. The only reason that say not to drive without it is due to the fact that the brake system is 65% rear and 35% in the front. Without the prop shaft (front drive shaft) it will not stay were you park it. It's just a concern about other drivers. The only thing you might notice is that you will have to lift the front end and turn the front tires to get the bolts to match up.

With all due respect, I believe either you misinterpreted what they told you, or they fed you bad information. The brakes have absolutely nothing to do with the front driveshaft, and don't care whether there is a front driveshaft or not. They are two independent systems. The brakes on a two wheel drive are identical to the brakes on a 4 wheel drive (from a hydraulic standpoint at least... Yes, I know the rotors are different). Brake proportion is unaffected by the front driveshaft being removed.

Without the front driveshaft, the front transfer case output can turn if the vehicle is parked on a hill. It has to do with the opposing forces needed to stop the center differential from turning. Without the front driveshaft, the system relies on the viscous coupling to resist the movement. Due to its nature, it will slip (if it's not damaged). The VC slipping is what allows the vehicle to creep in park.

 

[CHEESYPOOFS]

would using the parking brake make any difference in this matter or would it creep anyway?