If that happens only at that speed, and not when you are going faster or slower, I would suspect resonance. In any case, it would be best to have the car checked by a repair shop.
The transmission is not shifting in and out of gear or your front joint is going bad
Your front, left or right axle needs to be replaced.
Could be lots of causes, but most likely either rear differential issue or torque converter shudder in automatic transmission, though Ford is not nearly as common to have transmission shudder as a Chrysler is. Mine was the rear differential. (98, 5.4l). Mine was most pronounced when accelerating around a corner. Transmission shudder would most likely show up on acceleration at any time.
The sight of so much blood made him shudder.She shuddered at the thought of kissing him.Mention of that awful decade should make politicians shudder. Nutritionists would shudder at all the fat, sodium and trans-fats.Putting my future into the whims of the electorate makes me shudder.Bloggers often display postings that would make party censors shudder.The glider gives a slight shudder and the bottom drops out.
Warped rotor(s).
Coper
get your wheels balanced
Clutch bearing may be going out on kompressor.
I am thinking you have a rear wheel drive truck or suv????? Need more info, but I think the u-joint is very bad where it bolts to the rear axle. I would guess a 150.00 repair. The joint is 25.00. I hope this is usefull!!! ....
Only when accelerating, I would suspect a broken motor mount or bad CV joint.
Check the fuel filter or the fuel pump.
gradually accelerating