I have an 02 with a built tranny. Tranny has maybe at most 4k miles on it. Fluid changed after 1000 miles. Just recently it started quick shifting. The 1-2 shift used to be pretty firm now it feels soft then shortly there after there is another shift. We are talking like 1-2 seconds under normal acceleration. Then the truck wont shift again until about 45ish when its going into 4th. Any ideas on what it might be?