The fork is shown in Ariens Parts Radar in the Ariens web page. Plug in your model number and find the fork under "Friction Drive". I can't decipher how it is held in, but someone else may be able to.
2004 Ariens 11528LE, Troybilt Horse "Big Red" Tiller (original), Troybilt Tuffy Tiller (original), Sears LT1000 mower, Lawn Boy 7073 21" mower, Stihl FS55 RC trimmer, Poulan Countervibe 3400 chainsaw