Have a problem with shuddering from 30 to 45 mph. May be tranny issue.

What is your question?

I have had problems with shuddering from 30-45 mph all the time. Occasionally I will experience slippage. The slippage seems to happen when weather is cooler and takes awhile for the gear to switch out of 1st into 2nd. A mechanic told me it felt like torque converter issue. I was hoping to take care of the problem by replacing accessible sensors before delving into complete transmission repair. There doesn't appear to be any codes thrown...at least I wasn't informed of any. Is there a sensor or set of sensors that may remedy this problem. Tranny fluid is nice and red, not sure if it was flushed before I purchased about a year ago. If there is a sensor or set of sensors that might take care of the problem, what are they and where are they located? I have a 4R70W transmission in a Ford e150 5.4L Econoline Club Wagon.