New to forum 03 4x4 silverado question

!st of all I am new to the forum and it is really nice to see people helping others. I just bought my son a 2003 4x4 chevy silverado and I have a couple of questions. The transmission seems to shift kinda hard from 1st to 2cd the rest of the shifts feels very smooth no slipping is there an easy fix or is this major I have already changed the transmission oil and filter still the same and the check engine light is on could this tell me something if I pulled a code. It is really a clean and great running truck it has the small v8 and an extended cab if this will help any info will be greatly appreciated.

Come on guys help me

Welcome to the forum. Do you know if the truck has a shift kit installed or if the PCM has been reprogrammed for firmer shifts? Was a billet servo installed?

A trans capable scanner should be used to check for any stored codes. Need to verify line pressures are within spec.

Is the harsh shift when it is cold or hot? Or both?

//2000CAYukon