New to the forum. Have a John Deere LA120 with a 42" deck. Replaced the belt like 3 three times already with in weeks if eachother. When ever I disengage the mower drive belt, it slips off. Also, when I raise the deck, the belt engages by itself. Also, the belt looses tension when i lower the deck. Any help would be appreciated!!
Check all the deck pulleys, making sure that the bearings are not worn. Had the same issue on a JD unit last summer and found the idler pulleys were worn just a little, but when I replaced them the problem was solved. Also, I have never had any luck with JD if I tried to use a non OEM belt. You must use a John Deere belt, or problems will keep reoccurring.
