Change of gears need retuned?

[OKGMC4]

I'm looking at changing my 3.07 dana 36 rear over to the optional 3.54 or 3.75 gears. What I don't know is does the ecm for my 01' 5.3l have to be changed? Can't the shift points stay the same? And since I have a programmable electronic speedomoter I don't need it there. Just not sure if the ecm uses the gear info for anything else like timing or such. Thanks for any info.