I wish I knew the answer to that. On my 02 SSEi - it was on the passenger side back side of the block - it looked like it had an additional part to 'relocate' it for some reason. I think it was a tight fit between it and the cv joint on passenger side.
Just got back from putting over 1000 miles on the 03 Bonneville. Oil pressure gauge has been reading two clicks from the 120 mark the whole time. Seemed a little on the high side but I figured if it was really that high it might be spraying some oil out a gasket or two. Thanks for the heads up on what parts to change.
Changed it out yesterday. I thought a rag would be enough to catch the oil that would spill. Make sure you put a oil pan under it. Not too much but enough to make a mess. Glad I had a big piece of cardboard under it. Here is a picture of the new one and the old one in the back ground.
I used a 27 mm deepwell socket and small extension to get to it. The socket and extension fit over the top of the axle and brought it out just perfect for the ratchet.