found a parts list - for a 21 inch tiller attachment from AYP..

check bottom of last page for footnote on what Sears tractors it did/did not fit

Here is a link that might be useful: TS150CR parts list

I down loaded and copied all of the digrams.I still can not find any where showing what this tiller hooks too.
I have a JD LX176,Craftman 16 GTV,Rally riding mower 18 hp
& a old Broodmore Simplicity.I can't get it to hook to none of them.

NOTE: Side plates Nos. 27-28 support plates look like they might bolt to the front corner sides of the frame, and No. 29 center -plate would bolt to them on each side.
At the back, no's 40-41 might attach somewhere under the tractor frame. I would think the whole thing might pivot downward, to engage the ground for tilling.
NOTE: I have never seen one of these, i am just going by the line drawings of the assembly, and having knowlege of how other things work, in the land of mowing attachments, etc. HTH: Rusty Jones