Can I do this without damage to anything?

'97 Expedition (but the F150 forum seems more mechanically incline, no offense to the Expedition forum).

I'm trying to find the cause of a vibration in what I think is the front drivetrain. I was almost positive that it was the front driveshaft universal joints. I jacked the truck up off all fours and took her for a spin. The noise seemed to be coming from the from u-joint.

I took the u-joints off and they were still nicely lubricated (after 230,000 miles). My heart sank since this probably not the root of my problem.

I'm surely going to put new u-joints in but think I'll get them from the dealer tomorrow (if the OEM stuff lasted this long, why buy aftermarket, even though it's the same stuff? I dunno, just my OCD kicking in.)

So, I thought I would take the truck for a drive without the front driveshaft today (in 2wd of course) to see if the vibration was gone. Can I do this?

 

Oil leakage will be a problem. Why not just replace the ujoints and put it back together first. On the F150s the most common joint to go is the rear on the rear shaft. The vibration is felt through your seat.

 

I figured that there would be some reason why I shouldn't, which is why I didn't. Thanks so much!

Well, and since I pulled the #5 coil in the meantime and broke the bolt, I suppose the truck isn't going anywhere until that's fixed. Any other vehicle, I never break any bolts and on this thing, I break them right and left.

Maybe while it's down today I'll pull the rear shaft too, heck 230K miles is probably enough for any u-joint. I do have it up on jacks (all fours) with the drivetrain running and the vibration is definitely coming from the front.

I dunno, any more thoughts on where I should look? When I rotate the front wheels independently, the drivetrain is quiet all the way to the diff. There is just a slight tap sound (just one faint tap) when I change direction of the rotation. I suspect that this is either the CV joint switching directions or diff spline/gearing making a noise to move in the opposite direction.

While on the road at 60mph, it seems that the vibration is coming from the front right, but the wheel bearings seem to be quiet.

Any thoughts?

 

if you have not done the front wheel bearings in several years ( original?) I would suspect them. Two modes of failure are drying out bearing, that turns stiff and may cause a whine or vibration or both..... and failure of a ball bearing inside that causes slop, wobble, and noise. You can take off the wheel, remove the brake disc , then rotate the hub and notice any DRAG.. compare right to left to see what is normal. Initial failures may have very little noise or clearance, just a DRAG causing some vibration / minor noise.

 

as mentioned, I would pull the rear shaft and check the rear U-joint ..... it can vibrate thru the truck and appear to be coming from the front... Rear is most common other than front wheel bearings.

 

Good idea, I will do this - might as well. U-joints are easy and cheap.

I suppose that this is the next area to look at if the u-joints don't do it. The wheel bearings are original, but when I put new discs on about 2 weeks ago (the vibration was there at that time), all seemed good with them.

Thanks guys!

 

An F-150 is Part-Time 4WD, the front driveshaft does not turn in 2WD, which makes it easier to determine front drive shaft versus wheel bearing assemblies (wheel bearings and half-shafts always turn in both 2WD and 4WD).

Is the 1997 Expedition Part-Time, or Full-Time 4WD? Some vehicles have "AWD", but may have a selector to run 2WD only in one position. Can use that to check under what powertrain drive conditions the vibration occurs to help locate the source.