Random Driveline Vibration??? Can't figure out

[nobb]

This is weird and has never happened to me before.

I was on the highway doing ~110 km/h in 5th gear and suddenly the 4Runner developed a random vibration that lasted about 2 minutes then disappeared completely. There was no place to pull over, but I did slow down to 80 km/h and the vibrations remained in place until they suddenly disappeared. I did not feel at any point that I was out of steering control.

I couldn't tell if it was the front or rear that was vibrating, just that the whole vehicle felt like it was driving down a rutted road. The highway was smooth as I drive this section home from work everyday. As soon as I got home, I inspected the driveshafts, u-joints, front suspension, tie-rod ends, and steering rack. No play in any of these components, no random fluid leaks, nothing. The underbody and wheel wells were clean, so it couldn't have been dirt.

So I am stumped and haven't been able to reproduce this problem at all recently. Any thoughts? Maybe it's like the infamous "death wobble" on solid front axle trucks such that the vibration only appears when you hit just the right resonant frequency.

 

[mckennar]

I had a situation like this many years ago in a different vehicle when I ran over a piece of wire-debris. It wrapped around my rear driveshaft and caused some ridiculous vibrations.

I pulled over, unwrapped the wire, everything was back to normal.

So you may have had something stuck on a propshaft that caused an imbalance, then it broke/fell off?

Also... 6th gear? What kind of transmission are you running?

 

[nobb]

Also... 6th gear? What kind of transmission are you running?

Haha oops...edited.

Hopefully youre right and maybe some rope/debris got caught and flew off. I have no idea as the driveline appears clear now.

Thanks for the suggestion.