I have an 04 Chev Duramax with Banks package. 65k miles, never to hard on it. I recently got on it and it seemed to stay in 3rd longer not shifting at a normal rev shift. It seems like it continues to do this, however it shifts perfect under normal driving, only when I get on it, and only 3rd gear. Is my trans going, any info would help. I changed fluilds around 50 k, no flush though.
Thanks