1994 Mazda 626 Transamission problem, as I was told

The problem started when drive in 'D' sometimes I get this grinding noise but disappeared when put in 'S' or 'L' gear. Couple days ago, the car all of sudden got very sluggish at the beginning, and then at a light slope, it stopped. I turned off the engine and waited for few mins and the car will drive for maybe another 50metres and then the same problem. Some one suggested it is to do with the oil filter in transmission, the paper melted and had blockage which stopped petrol flowing. Not sure if this is the problem?