Excessive driveline vibration/rumbling

[pink_sleeve]

Trying to figure out what's going on. There is a ridiculous amount of vibration around 25mph and around 55-60. It does go away for most part after applying the brakes and coasting. It seems to not be as pronounced if you drive it like you stole it. But if you try to drive it gingerly the vibration is pretty intense and loud. The rear center driveshaft does have some play at the rear yoke where it connects to the 3rd member but I wouldn't think it would cause this much vibration. But then again I could be wrong. I've also now noticed the 3rd member leaking diff fluid from what appears to be out of the front of it. Maybe the 3rd member also needs rebuilt/replaced? If the third member was junk would it be rumbling/causing vibration? I notice it is pretty warm to the touch after driving around.

 

[ColtonAdkison]

Check U-Joints. Or put some grease in them. I had a U-joint gradually go bad on my Runner and it got to the point where it was doing the same thing yours is doing. Turned out the one nearest to the third member was cracked.. Best of luck.

 

[mckennar]

Just happened to me, you'd be surprised how a tiny bit of slop in a u-joint manifests itself in some fairly extreme vibrations.

 

[pink_sleeve]

What about the leaking from the front side of the 3rd member?

 

[mckennar]

What about the leaking from the front side of the 3rd member?

If your pinion seal is gone, that would explain the leakage. If it's been leaking for long enough, it may have lost enough rear diff oil that your rear diff is on it's way out.

Perhaps someone else with more experience in this field can jump in and talk about pinion bearing noise (?) and/or possibility of burning up a rear end due to a loss of oil and what kind of awful noises / vibrations that makes.

Edit: found this over at yotatech. Don't want to point you in the wrong direction, but I'd at least check it out:
http://www.yotatech.com/f2/pinion-bearing-failure-231908/