Let's go through what you are planning on doing:transmission oil, the differential fluids, engine oil, powersteering, and spark plugs changed. And also getting my brakes checked. hopefully that fixes the rattling.
actually i did most of those things because my E needed them not just because of the rattling. I only really wanted to change my power steering and Diff Fluids to see if that got rid of the noise but it didnt. Everything else was just due to my car needing it. Im convinced the rattling is probably coming from the right wheel rotor (looks rusted) hitting some brake shield (if that even exists on my E) I had a ford mustang that made this exact noise and it was the brake dust shield hitting the rotor. I took off the front wheels of my car and checked the brakes, and they looked fine, suspension feels good. spdrcr5 ill take your advice and check the wheel bearings and the bushings, (just need to find out how they look like). I did notice after lifting my car up that the right wheel wiggle just a bit inwards and outwards, towards the engine and outwards towards the sidewalk. as in if you grab the top and bottom of the wheel and pull the top and pull the bottom it moves just a bit and not the left wheel one. I may need to tighten something up here.