I have an older (1989) Craftsman rear tine tiller 17" 5 HP model # 917.299651.

The transmission is making a horrible noise, when in reverse, forward, or with the tines engaged. The noise happens after the first few seconds of operating the tiller in gear. There is no noise in neutral. Everything still works. I have the owners manual but no service manual. Anyone been there before and have any words of wisdom before I crack this open? It appears the whole thing will have to be gutted to see what I need to see.