Here is my sad story…I have a 1999 4Runner with 120,000. About 1 year ago I had the brakes reworked, replace the rotors, reworking the calipers, and then 6 months ago, I had the Transmission rebuilt and the Torque Convertor replaced. Just after the Transmission and Torque Convertor rework, I started picking up a strong vibration at about 65-70 miles per hour. The vibration does not happen each time you drive the 4Runner. However, when and if it does the vibration gets so strong at times, I am required to pull off the road, to stop the vibration, and then it may go several days without happening again. The person at the transmission shop checked the U-joints and did not see any problem. They also said that it could be the engine missing when the transmission goes into lockup, so I had it tuned up; replacing the spark plugs and wires, and that did not fix the problem. About a month ago, a new problem started happening along with the vibration. The vibration starts, but it may or may not have what Just Brakes called fading brakes. The brake goes ½ down and at times, and you think the 4Runner will not stop. The vibration can occur and not have fading brakes, but I have noticed that after a vibration event , if you come off the interstate at 60 or 70 miles an hour with strong braking, you get some vibration from the front wheels. I took the 4Runner back to “Just Brakes” at two locations and they say nothing appears to be wrong with the brakes or the ABS system. Both places drove the 4Runner and said they could not create the same problem. They said it might be the tires separating, so I took it and had the tires balanced and rotated, and Discount Tires did not see any problem with the tires. However, it appears the vibration has moved more to the rear of the 4Runner, now that the front tires were moved to the back. But, it would seem to me if it is the tires, then I should not be getting the braking noise coming off the interstate, and one more thing on two occasions I have smelled something like burning rubber when this happen, but Just Brakes says no signs of heat on the brakes. Sorry for the long read.

If you have the luxury of another set of rims(?) with balanced tires then try that.

Post your location-perhaps one of us would let you borrow a set in hopes of not being able to duplicate the problem. Then you know for sure it is indeed the tires.

So many things can cause vibration but you seem to have already narrowed it down to the tires themselves.

It's good you have gotten several different experts to drive it and venture an opinion. Pads nice and tight within the front calipers still? Any unusual wear? Perhaps get a 2nd brake opinion at a Midas or Meineke or other shop. I like Just Brakes myself-but we're all human. Maybe they are missing something. Your fluid level is staying consistently good? No leakage at the master cylinder or noticeable drips anywhere staining your garage floor at all?

One tire may have a separation or cord failure that is not detectable just by looking at it. Also I would presume the Torque Converter and Tranny work still covered under warranty so get them to take a look just for grins.

Good luck with this -it has to be frustrating but it will get better sir.