what controls the shifting in an auto transmition on 1997 Oldsmobile Bravada

the trans does not want to shift at 3000 rpms you have to take your foot out of it to get it to shift it just started to do this and got rilly bad in one trip to the store

Asked by for the 1997 Oldsmobile Bravada
Check the transmission oil level perhaps it needs to be serviced or worse has a serious internal transmission problem.