Need a little educatin' gang. Are the front axleshafts and driveshaft turning on our trucks when in 2 wheel drive? Not sure if we have vacuum hubs like in previous years or not. Main reason I ask is am looking at the leveling kits and am wondering if the small lift will adversley affect the cv joint life during highway use. Thanks in advance for any info and advice!

 

Leveling kit will not harm anything. No they do not turn except when engaged in 4 wheel drive.

ViperFX4

 

Thank you sir...let the moddin begin!

 

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CV JOINT´S TURNS ALL TIME 4X2 OR 4X4 MODE, LIKE PREVIOUS MODELS.... NO HUBS ON EACH SIDE!!!!

 

Well great, now I don't know what to think!? Anyone else?? whose right here? Guess I'll put it on a lift and try it that way.

 

It doesn't matter if they are turning or not because the joints will not wear without any pressure on them.

 

good point!! osbornk


here is a picture cv direct bolt to disc..

 

You'll notice there are vacuum lines running to the hubs. They only engage when in 4 wheel drive and the drive shaft to the front axle only turns when the transfer case is in 4 wheel drive. If you try it on a lift be sure the truck is running because I believe the vacuum is used to unlock the hubs, not lock them.
This would also be interesting to confirm!

 

Lobo, where did you locate the custom fender badges.
I'd be interested in a set that say Thunder instead of Lobo.
Let me know when you get a chance.

JR

 

WRONG. I don't see a vacumme line, I see a wheel sensor wire. That is the point of CV joints so they can spin all the time without turing or tire wear issues. The disconnect its at the transfer case and at the front differential. That prevents the front driveshaft from rotating.

 

Ok, here's the scoop. Since I work at a Ford dealer I got off my lazy a** and asked my shop. These trucks do have vacuum hubs, thats the bigger line you see running to them. The smaller wire is the abs sensor wire. When in two wheel drive none of the front drivetrain is turning until you engage 4 wheel drive. The motor on the transfer case spins up the case and front shaft to match road speed and the hubs engage and viola..4x4. When you are in 2 wheel drive and shut off truck the hubs also engage until you re-start it...kinda strange there! Hope this helps and thanks again for all the replies.

 

Thanks for confirming that the hubs are unlocked by vacuum.
This means that with a lift the angle of the CV joint is only a factor when 4 wheel drive is engaged. Which was your original question...

 

I have to agree with torresu, not that I doubt what sajeffc is saying, but when the truck is rolling (regardless of 4x) the cv boots and joints are moving. The front diff should be moving as well. The output shaft from the transfer case to the front dif is not engaged. Thus leaveing the front dif and cv's to move freely. When the selector is switched to 4x4 the transfer case is engaged and spins to speed then the output shaft is engaged.

NOTE: THIS IS HOW MOST VEHICLES WORK AND IS GENERALL KNOWLEDGE NOT SPECIFIC TO THE NEW FORD.

Thats why for instance some people of different vehicles change from auto hubs to manual so they can disengage the cvs from moveing and thus reduce wear. This also dramatically reduces the friction of the front drive train helping with gas mileage.

Just some more info for the fire.

If this is the way it is, the lift willl just wear out your cv boots quicker. Unless you put a load on the cvs and stay in 4x then you would get some wear down the road.

 

Ok gang, heres the gospel from the 2004 f150 shop manual page 308-07-2 (sorry for long post). "Principles of operation. The transfer case is equipped with an electromagnetic clutch which is located inside the case. This clutch is used to synchronize the front driveline. When the mode select switch (mss) on the dash is turned, the 4x4 module (pcm) activates the electromagnetic clutch and powers the transfer case shift motor...to be cont next post!

 

"When the shift motor reaches the desired position, power to shift motor is removed. When the transfer case front and rear output shafts are synchronized, the spring loaded lockup collar mechanically engages the mainshaft hub to the drive sprocket. Finally, the front axle integrated wheel ends (IWEs) are engaged and the electromagnetic clutch is deactivated." So the IWE is what they call our "hubs" and they do allow 4x2 operation with NO front drivetrain movement. This makes the leveling kit a non issue for 95% of our driving. Hope this answers all!!!