Auto Trans Help/Skips D
 

70' C10 w/350, not sure on the trans type yet. I changed my trans fluid and filter, and drove the truck afterward and everything worked alright. Next time I drove it All the gears work but it skips over drive. It goes into P, R, N, skips D, and goes into 2, and 1. It drives in all the gears that it goes into. This truck has been a daily driver and haven't had issues before. I just skips D all together, and I don't get it, but I'm not a trans guy.

Any help is appreciated