Is ok for me to have dex 3 instead of dex 6???

For a 2000-2005 SSE/SSEi yes. But go with DEX VI if you can, makes a measurable difference. Wal-Mart sells the DEX VI at a much lower price than the major chain auto parts stores.

I jst got my trans redone and the shop put dex 3 in thr. Shld i ride tht out or change it immediately??

Well you can ride it out but GM released a TSB telling owners to replace Dex 3 with Dex 6. TSB#04-07-30-037E

Great question...I wanted to know the same exact thing...as im having my trans rebuilt also

Has anyone heard of lubegard platinum...?? An additive for the transmission ..

I've heard of it, but not used it, I have used their Dr. Tranny Shudder Fixx, and oil additives, and they are pretty good.

If you ever get any shudder in the tranny, and want to get a little more life out of it, then this helps.
http://www.lubegard.com/~/C-230/Dr.+...t+Shudder+Fixx