What could be causing rattling, hard shifts, and a fluid leak? on 1999 Toyota Camry

Rattling is worse when driving on bumpier roads, hardest shifts are first reverse out of our driveway, and the fluid leak is brown and we were told that it seems to be a combo of power steering fluid and oil, but I am not sure which oil.

We recently had the starter and a leakygasket replaced that was causing a check engine light about 20 miles after each fill-up (PO466 code).

Asked by for the 1999 Toyota Camry
Sounds like at least 2 seperate issues. First the rattle may be caused by worn sway bar links , quite common. Second what 'gasket' was replaced that was causing the code? Did replacing it stop the P0466 from returning? Third, has the trans fluid level been checked? Warmed up on LEVEL ground (HINT- not to be a wise-ass but put it in neutral, if it rolls , you're not on level ground and the reading won't be accurate)........Ever try eating oatmeal while hanging upside down?