05 T4R - 185k miles - V8 -

My 4runner has had a fairly noticeable vibration from the rear of the vehicle for sometime now and I am finally to a point where I want to correct it. It is noticeable above 60MPH and is to the point where the passenger seat shakes fairly bad. Much MUCH more than you would consider normal.

-Removed the rear drive shaft and drove it. Vibration still there.
-Balanced tires, and rotated as well, no change. In fact rear tires are NEW.
-Removed wheel spacers, no change.


What else should I be looking at? Could it be a bearing, bad shock / shocks? I have Bilstein's and they are fairly new so I am ruling that out at least for now.

Trying to ID this myself where possible. Worst case I will bring it to a mechanic.

Any noise or just vibration? Does it change when turning left or right?

Check the pinion bearing.

How about changing the differential oil and looking for metal in the oil (MIO) first. Then rear wheel bearings.

Lots of rear vibrations posts lately.

Check the pinion for play.
Check wheel bearings for play, turn them to listen for noise.
Check control arm bushings.
Check track bar bushings.

Lots of stuff back there. If no clicking or noise when making sharp turns I’d say your rear diff is good.

When was new fluid done in the rear diff or transfer case?