At 42 MPH give or take 1 MPH my 95 SC400 shutters and acts like it is trying to shift in and out of another gear.

Any ideas. Thanks for the info on the dimming lights when breake if hit.

 

You can try to flush the transmission first( a complete flush with 14 quarts of fluid). I've seen a lot of this problem on the older LS400 and SC400. Some dirt bluid up inside the torque convertor can cause this problem.