Stuttering while changing gears.

Probably fluid shutter.
The torque converter caused the rumble strip effect.
The best fix for TCC shudder is a pan drop and fluid/filter change. But a flush will do it as will some friction modifyer additives made to solve the shudder problem.
Neither is as good as a pan drop and filter/fluid change. Most fords have a converter drain plug too. So you CAN get ALL of the fluid out which is what many flush shops preach about.

Thanks, I will get that checked on