I found DTAC Solution Number M11867 from the John Deere Horicon works on timing belt slippage and blade contact on the web. It does a through job of explaining how to set up the belt tension and blade alignment on the Freedonm deck.

I have a used LT155 with the Freedon 42 deck. I saw it mow before I bought it and when I got home it made 3 beautiful passes in my yard before I heard the blades hitting.

They had been sharpened but I believe not torqued correctly and became loose; however the blade timing is also off.

I removed the deck and cover and it appears someone had been there before me. I am positive the tensioning idler has been out and I need to know how to return it to factory spec. Presently it is centered on the slide(not sure correct description here). I took it apart after I used the above tech sheet to the letter and the belt still slipped. The belt looks new as did the drive belt so it is my guess that a previous owner had replaced them. Woman who sold it has no clue what had been done prior.

The tech sheet indicates tensioning of the idler nut is critical to prevent slippage so I hope someone can guide me here. Thanks Tabonga...New Member!