If its got a 8 to 10 speed transmission and 3 or 4 range rear axle... 30+ MPH is easily not out of the question and still be able to pull a crud load drag in 1st gear in low range. Heck they show about 35KPH in the video.
He could barely stay under Redline backing the thing out of the shed and was no faster than 4 MPH.
My Dad's John Deere has a Diesel with a Turbo on it. In 15th... the thing MOVES OUT at about 20 MPH at max RPM... and its a single range. Could get a 4 range axle with a 4 or 6 speed transmission.
On the Engine:
http://www.tractorda...-4450-engine.html
They only show 2 transmission choices... the 15 speed with single axle range or a 4 range with 4 speed transmissions.