This is going to see like a really odd problem, but I'll ask it anyways. The transmission on my Aurora always has shifted very firm since I bought it. You can feel every shift. It'* a quick firm shift each and every time. (it'* a 4t65E with the 3.27 gear ratio.) My brother'* 2000 SLE with the same transmission shifts smooth. You can almost never feel it shift. My question is if there might be something wrong with my transmission, or if it has more to do with maybe the PCM programming between the two cars? It'* very apparent on the aurora though, the shifts can even be called rough at times when shifting. the aurora has 44K miles, the bonneville has 62. Even the SSEi shifts smoother. Just curious why you can feel the shift very apparent on one 65E then on another you don't feel a thing. Odd.