Automatic Transmission Torque Converter problems of the 2007 Toyota 4Runner

I have a Toyota 4runner sr5 2007 4x4 v6 with about 90k and seem to have developed the rumble strip issue as well. I am curious if the op has gotten any traction on getting anything figured out. It seems like it must be the "lock up" feature of the torque converter in 4th and 5th gears. The vibration comes on at the end of 3rd gear when the rpms are about 2k or so. Then again as it tries to shift up to 5th. In our case as well, putting the trans in '4' instead of 'd' totally eliminates the problem. I wonder if some sort of reflash could fix things. My current plan is to double check the level on the fluid and be sure the zerks are all lube up. It is unfortunate that this has come up as we love the car otherwise. If something does need fixing, I am in no hurry to head to the dealership, and I am afraid that a more local type transmission shop will not have much experience with these new super fancy sealed transmissions. I hope that I am wrong.

The contact owns a 2007 Toyota 4runner. While at a stop light and attempting to accelerate, the vehicle hesitated to respond. The vehicle was taken to the dealer, who diagnosed that the transmission needed to be replaced. The vehicle was taken to an independent mechanic for a second opinion, who diagnosed that the torque converter needed to be replaced. The vehicle was not repaired. The manufacturer was not made aware of the failure. The approximate failure mileage was 71,000.