This sh$# stinks to high he##. I've been reading old post abt it and have several questions ....I have a 2000 pontiac Bonneville ssei...should i change it or top it off and wht shld i use its recommended by u guys tht i use a couple of formulas the most popular one is mobil1 full syn 5w-30.....help me out fellas.

I use AMSOIL for everything, but Mobil1 is specifically mentioned in the tech manual as a suitable replacement.

Also, I'd change it.

5w-30?? Is this the right weight/??

Yea thats correct.

I've done several oil changes and have been using M1 5w30 for several years now.

How often??

No reason when it shouldn't last for years. But if you do it once a year you will be just fine.

Y does it stink so bad??? Is tht a sign it needs changing??

I haven't encountered a gear oil that doesn't smell horrible. Once you change it to motor oil it should smell better.