Hello,
This is my first post on my First Ford Truck.
I just had all this work done because the front end was loose and vibrated over 50 mph: New control arm/ball joints, upper and lower, all new u joints and front end alignment. Afterwards the truck is definitely tighter and handles better but from the moment you start rolling there is a noise from the front end that sounds like I'm riding on some big off road tires which continues all the way to about 55 mph where the front end has the most vibration. You can't hear it outside by sticking your head out the window but you feel it right below your feet. So while it was up on a lift we spun the drivers front wheel and you can't hear it at the wheel but if someone is in the cab they can hear/feel it. So as someone was spinning the wheel we went underneath and traced it the the yoke of the front diff, you can put your hand on it and feel the vibration. There is play in the pinion as you turn the front drive shaft left and right, should this be tight?
What do you think this is, a bearing?

If the front diff isn't engaged/I'm in 2wd the front drive shaft shouldn't be spinning should it? It must be because that is where the noise is coming from. Can I stop it from spinning somehow? Duct tape?
At first I thought maybe they put the drive shafts in differently after replacing the u joints but that wouldn't cause the noise when your only going 0-5 mph and like I said this noise is there as soon as you start rolling. It wasn't there before the work was done but the vibration at 55 mph feels just like it did before. Sorry for the long winded post, just wanted to get all the info out right off the bat.
Thanks

 

You are correct. The axle nor the driveshaft spin while in 2WD. The only thing turning inside the axle is the input from the left CV axleshaft is spinning the spider gears inside the carrier, but that's it. The carrier itself shouldn't even be turing because the driveshaft isn't. Even if you had a bad pinion gear bearing or something else, you wouldn't get it while driving in 2WD.

Extremely funny you brought this up as I'm chasing the exact same problem, literally. Except mine only occurrs right around 20mph. By 25, it's gone. But I'm starting to think mine is the mud tires and they just have a particular resonance around that 20 mph point cause I sure can't find anything else. Mine is only in the cab also...I had the wife drive around at 20 with me hanging out the door...NOTHING!

Anything like hub beargins or something like that would be audible outside the truck and you'd know it from spinning the wheels on a lift.

Good luck to us both and please let me know if you find something. I've given up, LOL!

Oh yea...WELCOME!

 

You either have a sticking front differential actuator that's not disengaging the front axle or the solenoid that is for 2wd that disengagues the front diff is bad and not working, also check the vacumm lines they could be leaking.

 

That would mean the axle half was connected and by default the carrier and driveshaft would be spinning while going down the road...this is not the case on my truck. I've watched; the driveshaft does not turn. If it's not turning, nothing on the inside is turning. Don't know if rrcade has checked his or not.

As a side note though...how do you check those to see if they're bad? How do you check to see if the axle thing is failed to engaged? Is there a sure fire thing to look for? I known this system is different from the '04 and up, but that's about all I know about it.

 

My bad man I thought u had the same issue as rrcade. I know the spider gears turn in the carrier in 2wd but that's it. Let me know everything u have checked and your exact problem and I might can help, I'm havin a hard time understandin your issue. Sorry man

 

Steven, I am having the same problem, except my noise occurs at a much different speed than his. My noise only occurs around ~20 mph and the noise is gone by ~25 or so. My driveshaft is not turning while driving in 2WD, so I'm assuming I don't have anything funny going on with the axle disengagement or anything like that. My front hub assemblies are brand new. I'm starting to think my noise actually is the tires and that they just have a unique resonance around that 20mph window causing the noise I'm hearing. It's just weird that it's only in the cab.

 

Hmm I got it now. Yea it sounds like your 4wd system is perfectly fine, I guess something could be up with the cv axles since they turn all the time even in 2wd but I don't think so I guess its worth checkin into. It definatly could be a tire issue.

 

I'm gonna have to really start trying to figure this out as the vibration is getting worse. Could someone check this for me-While the truck is in park and in 2wd should the front driveshaft spin freely? Because mine doesn't I can twist it a little clockwise and counterclockwise and it feels engaged, also while in park if I push the front wheel forward a little the front drive shaft also turns, should it?

 

No the front driveshaftt should be able to turn by hand in 2wd.

 

Any idea why mine is engaged, it s a 2002 so I don't think it has any vaccum control does it?

 

Theres 2 solenoids behind the battery and vacuum lines check those out I'm guessin the solenoid that shifts the front diff back into 2wd is bad.

 

Thanks, I'll see if I can locate them and check them out.
I also just checked the front drive shaft in Neutral and it is engaged also just like it was in Park. The thing is I'm Not in 4wd, there was some snow today and I punched it and only the rear wheels spun so the front drive shaft is spinning but I'm not really in 4wd.
If this thing were to work correctly the front drive shaft shouldn't spin At All in 2wd? (Should it actually disengage from both the front Diff and the Transfer case?)
Would there be anything wrong with taking the front drive shaft off just to see if it took away the shaking?
Did I mention I hate cars/trucks?

 

OK rrcade, here's some thoughts/points for ya...

-In 2WD, the driveshaft should turn completely free by hand.
-In 2WD, the driveshaft should not turn while driving down the road.
-If not in 4WD, what you described is accurate. The front axle is engaged but the transfer case is not in 4WD, so what you described (rear wheel only spin) is correct.
-Long story short, your front axle is engaged somehow...vacuum problem as described, etc.
-There's a vacuum solenoid on the right hand side of the axle under a black plastic skid plate with two vacuum lines running to it; check that for connection, condition, etc. This is what engages the two halves of the axle shaft to 'make things work'
-Yes, it is completely OK to drive around with the front driveshaft removed. However, this won't tell you much because the axle and all its internals will still be turning the same as it is now in your current condition when you drive around.
-The vibration part I don't get. You should not be getting any serious bad vibrations just because you're driving around in 4WD for all practical purposes.

 

Found the problem, the linkage under that little black plastic skid plate you described was completely packed with dried up mud-so much that it wouldn't allow the solenoid to move. I chipped it away with a screw driver and it was immediately freed up and working. My front drive shaft is now disengaged. So now my noise is gone in the front Diff.
As far as the vibration I'm thinking two different things:
First, I just had new front and rear U joints installed and while they have white paint marks on the shafts it appears that they may have installed them differently than original(you can see the old pattern on the flanges of the diff and transfer case) Now I'm not sure if the important part is to assemble the complete drive shaft with u joints the same way it was only and how it's rotated when bolted to the diff/transfer case flanges doesn't really matter?

The second thing I think it probably is: Intake manifold leak. I just had the crossover section start leaking coolant and also noticed the pcv valve was bad which both seemed to make the engine randomly stumble a little and shake.
So I changed PCV, put some Bars leak for intakes in and Seafoamed it and now so far no more leaking coolant and haven't noticed any shaking yet, we'll see what happens.