To change the transmission modulator valve in a 97 Pontiac Bonneville you will first need to lift the vehicle off the ground. Then, remove the vacuum hose and the defective valve. You can then replace with new, and replace the hose.
The bearings are not replaceable, they are a part of the rear hub assembly - the studs and the bearings are pressed in - replace the whole hub assembly - 4 bolts are holding it. Rear bearing/hub bolts (new only) are to to be torqued to spec. [2000 Montana - 85 Nm (63 lb ft)]