I was mowing in a field - yes I know - don't even go there- but my mower got stuck. It is a Gravely Promaster 18-H (300 Series) with a Eaton 851 Transmission. I pulled the lever you are suppost to to pull it out. But somehow as I was pulling the mower the lever got pushed back. Now it will not go. If I really give it gas it will just start to creep.......... Belts are good, fluid is good all normal stuff to check is okay. Dealer told me it was an o ring but he doesn't work on the transmission....... hummmm makes me wonder if I really did a good thing buying this mower BUT I love this mower - since this has happened I have been using a Cub Cadet my hubby wanted really bad and I hate it. PTO cuts off ALL the time since I don't weigh enough for the little safety swithches. Please tell me where to start on my Gravely transmission. I have the illustrated parts list.... but the o rings seem to only seal fittings. I know I can do this - just get me started.