Default Caterpillar Forklift



I have a Caterpillar Forklift Model #V40B - Serial # 81M03630 that I am having a couple issues with. The first is the grinding of gears when shifting from forward to reverse and back again. It has a wet clutch that I have adjusted and also pulled the top cover off to check if the clutch disc is free when clutch pedal is engaged. It all seems OK. I have also changed the tranny oil from what looked like lite transmission fluid to 80W90 oil, still not much help. Any help here? I also have another propane problem. When ignition is on or when the engine stalls, the engine will flood and will not start. I have heard a hissing sound when I accidently left the ignition on for a period of time. Also when I bought this forklift, the engine oil was milky and I suspect this was from being flooded to many times. Is this possible? Any input would be appreciated. THANK YOU