CAUTION! AWD Front Drive Shaft Removal --Drifts in park.

[teklenmax]

Joined the darkside and removed the front drive shaft today. Noticed right
away no binding and popping on tight turns. Everything seems to move
freely now; hard to explain before seemed like the truck was binding up
and being held back somehow. Drives great & noticed no problems or loss of
power; drove about 100 miles today no issues so far.

Parking Issue Discussed here:
I am using the parking break; but I did not notice any drifting. When put in
park the transmission seemed to hold truck just fine even on an incline. Will
continue to use the parking break anyway.

I will try to keep giving updates here on my darkside adventure.

100 Miles and no issues.
___________________
Brian
96 5.0L AWD w/Bad TC; Now 2WD by removing front driveshaft.

 

[99SportX]

The front output is directly linked (mechanically) to the input. The link between input and rear output goes through the viscous coupling. With the front shaft out, if you have a friend (that you trust to not run you over) hold the brake and put the vehicle in drive with engine running, take a peek under the truck and you will see the front output spin real slowly. I saw this years ago on a friends 98 XLT. We were very confused at the time as we did not know there was a viscous coupling inside. The viscous coupling slips slightly and is allowing the front output to spin very slowly even though the rear is locked from moving. Once the speed difference is sufficient, the fluid will heat up and begin to lock the coupling up in an effort to equalize front/rear shaft speeds. I am sure it happens fast when you hammer it from a stop without a front shaft in. So fast that you probably don't feel any delay. I know I don't. I am not sure what happens when a coupling fails. Does it lock solid, or provide no resistance leaving you pulling with just the front wheels (or none if you have no front shaft)?

This is my understanding so far. If I am wrong, please attempt to correct me. I really want to pull an AWD case apart as it is the best way to learn. People can post all the pics they want but I won't really understand it until I have the parts in my hand.

 

[jseabolt]

If you take out your front driveshaft on a 1998 5.0 AWD Explorer, it will not stay put in park.I had my driveshaft go bad. I was too cheap to buy a new genuine Ford driveshaft. I decided I dont need all wheel drive in Florida.One day the wife noticed the Explorer had backed itself half way out to the street.The parking propertys are 65 % to 35 %. The front driveshaft controls 35 % of your parking.I have found a used one to remedy my problem. Weird huh ?

I know this sounds DUHHH but looks to me like setting the parking brake as a fail safe would remedy it rolling out of gear? I always set mine even on the slightest incline and sometimes on flat ground just out of habit.

This maybe apples to oranages but a guy at a car show told me never to trust the parking mechanism on a Ford C4 transmission. His Fairlane popped out of park and rolled down a hill.

 

[teklenmax]

Yes I can confirm it does drift in park; now . I always use the parking brake when leaving the vehicle unattended and a wheel chock. When I was out working; I just put the vehicle in park as I was sitting in the vehicle, doing computer work on a carwash (IT Tech for carwash company), and the vehicle did start to roll back as I was parked on a slight incline. Thanks to all who posted about this before as I have been using the parking brake and wheel chock when parked at home or parked vehicle unattened.

Have about 500 miles since I have removed the front driveshaft and everthing
is riding smooth so far and have noticed no issues; am quite please to not hear the popping baning noise anymore from dead stops or when making hard turns from a stop. Also feels like it handles better in all turns. Just an update.

___________________
Brian
96 5.0L AWD w/Bad TC; Now 2WD by removing front driveshaft.
05-28-2010 08:21 PM

 

[jseabolt]

Have you noticed any increase in gas mileage?

My 68 Fairlane also has a 302 and get's about the same mileage as my Explorer.

But the Fairlane weighs about 1000 lbs less and doesn't have AWD. You would think with all that fancy computer controlled crap under the hood gas mileage should have doubled after almost 30 years of production.

But the Explorer makes about 20 more HP though....

 

[fordman1977]

I've got a 97 Explorer and have a binding at slow speeds, a whining noise at low speeds while driving straight, and a loud whine at a low speed turn. I think I actually have two problems. I think the VC is toast and it has damaged the frontend as I can see the front pinion leaking and I've sure I have a ring and pinion whine under tip in conditions. Opinions please...... I want to be sure I'm on the right track here guys.

 

[safn1949]

I've got a 97 Explorer and have a binding at slow speeds, a whining noise at low speeds while driving straight, and a loud whine at a low speed turn. I think I actually have two problems. I think the VC is toast and it has damaged the frontend as I can see the front pinion leaking and I've sure I have a ring and pinion whine under tip in conditions. Opinions please...... I want to be sure I'm on the right track here guys.

Pull the front drive shaft and take her for a spin.Then see if some or all of the noise goes away,I assume you have checked the differential fluid level.

 

[fordman1977]

Will that eliminate noise from the front diff? I assume that the ring and pinion will spin with the c/v axles right? What kind of noise should I expect from the transfer case if the VC is toast? We just serviced the transfer case and the fluid was very dark.

 

[AE86PandaDude]

it wont remove all of the noise when you take the front driveshaft out but it will remove most of it since when you remove it, the pinion is now stress free and it will just free spin as you drive it around

 

[teklenmax]

Will that eliminate noise from the front diff? I assume that the ring and pinion will spin with the c/v axles right? What kind of noise should I expect from the transfer case if the VC is toast? We just serviced the transfer case and the fluid was very dark.

Mine was only feeling like binding and making lots of creeking, crackling noises. Also if I too off full power popping and banging; same if i tried to make a sharp turn from dead stop. This binding and popping would get worse if I was driving long distances. Did not experience the the whining you described. Sounds like it could be someting else if it is a chirping like a bird chirp sound that could be your Crank Angle Sensor? Had that problem last year. Hope this helps.

Brian
96 5.0L AWD w/Bad TC; Now 2WD by removing front driveshaft.

 

[teklenmax]

Will that eliminate noise from the front diff? I assume that the ring and pinion will spin with the c/v axles right? What kind of noise should I expect from the transfer case if the VC is toast? We just serviced the transfer case and the fluid was very dark.

Are your front or rear tires heavily worn? I think I did my TC in by not rotating my tires enough my rear looked brand new with 80,000 mile on them; but the front looked heavily worn especially on the outside. I know need rotate and alignment, this was my first AWD and I suck at getting regular maintenance; I know now.

Remove your front Driveshaft and see what you hear is not hard 4 bolts each end. Don't forget the emergency brake everytime and for safety a wheel chock, Harbor Freight has a big assed rubber one with eyebolt for $11.99.

Brian
96 5.0L AWD w/Bad TC; Now 2WD by removing front driveshaft.

 

[fordman1977]

UPDATE!! I removed my front drive shaft and parked in on a large hill on my land. NOTHING! I couldn't make it move when in park. It didn't move for over 2 hours. I'm convinced, the VC is toast. I have driven it 135+ miles now with the front shaft out. NO frontend noise but I'm still sure that the center section is done because for the front pinion seal leak, bearing noise and the ring and pinion whine under accel at slow speeds, and the 1/2 in of slack it has. I've seen them on Ebay cheap and I'm not afraid to swap it out so when I get the transfer case issue fixed I plan to replace it.

 

[teklenmax]

Do yourself a favor and use the parking break and buy an wheel chock or at least use a brick to chock the wheels mine rolled out into the alley overnight on day 5 of having the front driveshaft removed. I was only on a slight incline too. It will drift when you least expect it.

___________________
Brian
96 5.0L AWD w/Bad TC; Now 2WD by removing front driveshaft.

 

[hotrod31]

I'm with teklenmax on this one, I have driven with no front drive shaft for 2-3 weeks now and it does creep in park(trust me)! apply those emergancy brakes guys!

 

[2000LXS]

I found out my front drive shaft splines were stripped after I came out of a Dunkin Dounuts and my truck was about half way down a hill allmost in the street. I was inside for about half an hour with my wife and son.

Yea they Drift

 

[fordman1977]

Mine finally did drift! I was cooling off from mowing and actually watched in click back a few feet in about 15 mins. I had the ebrake "on" but it wasn't tight. My fault. It's strange that it took driving it over 600 miles for it to begin to do this. Before it seems that the VC was locked together. Either way, the transfer case is getting replaced. Thanks for all the help guys.

 

[OneLever]

Feedback

I drive a 1997 Mercury Mountaineer 5.0L V8 with AWD. I removed my front driveshaft 8 months ago which was just over 5,000 miles ago. The CV joint boot on the aft portion of the shaft (where it connects to the transfer case) had torn and the bearings inside had gone out. This created a very loud clicking sound which varied directly with vehicle speed and was hard to pinpoint audibly. Removing the shaft solved the issue completely.

After reading this entire thread I would like to point out something about SoNic67's arguments. From the descriptions of how the viscous coupling works it is apparent that the fluid heats up and becomes nearly solid when there is an angular velocity difference between the front and rear driveshafts. This is normally prevented when all four tires are on the ground rolling because the front and rear tires travel roughly the same paths and thus usually rotate at roughly the same speed.

When the front driveshaft is removed we are left with a 10 lb. free spinning mass where it used to be. Now anytime the angular velocity of the rear driveshaft changes the viscous coupling kicks in and applies torque to the free spinning mass to make it spin at that new velocity. What is being overlooked in the prior arguments is that it only takes a small momentary initial torque force to accelerate the free spinning mass to its new speed. The reason the force is small is because it is such a small mass, and it can be made to rotate with little friction. The reason the force is momentary is because once the mass is brought up to speed it will remain there by virtue of inertia. The coupling will have to kick in slightly to counteract friction forces on the mass, but not to the point of becoming solid which is what heats it.

Now consider the opposite case, where instead of allowing the 10 lb. mass to rotate freely we freeze it in place with perhaps a crowbar. It would always be sitting at rest while the rear driveshaft was rotating to move the vehicle. Meaning that there would always be a large angular velocity difference between the fixed 10 lb. mass and the rotating rear driveshaft. The viscous coupling would always be hot and attempting to make the fixed 10 lb. mass move. This would likely lead the coupling to fail after a short time.

Finally, I would like to say that I always park with the parking brake on, and that I have never had the vehicle move even while parked on slight inclines during this time. If parked on a steep incline the vehicle will begin to slip slowly as what sounds like the parking brake gives way an inch or two a second. Something I believe has more to do with worn brake pads than lack of transmission parking action. As this thread states though, you should not rely on transmission parking action alone to hold the vehicle still. Use the parking brake and perhaps chock blocks.

 

[zero_chance]

One levers thoughts are one hundred percent spot on as they relate to how the VC works in this particular setup. And the TC is not trying to achieve a 50/50 split in power as someone assumed under normal driving situations. Its closer to 65 rear, 35 front.

 

[ford99_1979]

One levers thoughts are one hundred percent spot on as they relate to how the VC works in this particular setup. And the TC is not trying to achieve a 50/50 split in power as someone assumed under normal driving situations. Its closer to 65 rear, 35 front.

So let's say my transfer case is functioning fine and I remove my front driveshaft to do some rear wheel dyno tuning. The viscous coupler would not overheat causing damage ?

If you read this thread you see many different opinions. I just want to know if I can safely run on a dyno with my front driveshaft out for tuning purposes?

 

[zero_chance]

Ford99, while I certainly respect everyone's opinions, I can assure you that a normally operating transfer case with a VC will still function normally after removing the front driveshaft. As has been stated, the relatively small mass of the front coupler will easily be spun by itself with minimal, if any, stress to cause slippage / overheating. Driving with the front driveshaft connected puts more stress and changing conditions on the VC than driving without it connected. You will be fine. I think the misconception on the matter, at least from past experience, is that most people incorrectly think that without the front DS connected that the forward portion of the VC is either spinning too fast or too slow compared what it would be spinning with the front shaft connected. The main reason not to do this is the reason that is well known, which is the tendency for the vehicle to creep.