Not so good vibrations

[jse51599]

I have a problem with a vibration on my late 99 4x4 which feels like it is coming mostly from the front, around 40 mph then again at 70 mph. I purchased the truck recently and the previous owner replaced the ball joints; other than that I don't know much concerning the front end parts other than the fact that it passed a state safety inspection(probably don't mean much). I had the tires balanced and then I rotated them, but the vibe is still there. Anybody have any other ideas other than blindly throwing money and parts at it. Thanks in advance.

[JDM-POWERSTROKIN]

check all the u-joints in the front end

[jse51599]

Even the front driveshaft; I assumed it doesnt move since the hubs r unlocked? How do u check the u joints in the axles?

[JDM-POWERSTROKIN]

jack the truck up and visually inspect the u-joints while you spin the tire back and forth and look for excessive play or any noise

[jse51599]

Thanks ill check it out.

[NoRalPh]

Manually LOCK the hubs and see if the noise goes away.....

[jse51599]

If the hubs are locked or unlocked it still vibrates.

[cghoerichs]

2 piece drive shaft? See the posts regarding vibration and clunk at speeds and when starting and stopping. If not 2 piece disregard.

[jse51599]

do you mean 2 piece front driveshaft? The front shaft has what looks like a cv boot towards the front of the truck (differential side).

[cghoerichs]

No, the rear drive shaft, but it often sounds like the problem is coming from the front drive line of the truck or even the t-case. It is the shaft behind the transfer case. Most F-X50's have them. There is no grease fitting on them and they get dry and cause all kinds of noises and vibration. Once taken down and greased lightly the problem goes away until it dries out again.