I am concerned, my saab is tranny is acting up and I am hoping It is just the fluid but l do not know if l can add tranny fluid if l do not know what was in there before.

Use only the fluid recommended by the manufacturer. If unsure, call a dealer.

Incorrect fluid can ruin a transmission.

If you think the incorrect fluid is in the tranny, take it to a transmission specialist. They would drain it and add the correct fluid. Do not have it flushed, that can cause damage.

Your transmission takes the standard Dexron fluid. Why add the higher priced synthetic (model years 2002 and up) especially if the problem is not the fluid. If you are unsure of what is in the transmission then drain it completely at the 24mm drain plug on the bottom of the transmission and then refill it with 4 liters of the Dexron fluid. Most often if there is a problem with these transmissions, it is not the fluid.

ATF 3309 (SAAB P/N 93160393). Please always use SAAB specified oil. Do not mix. If in doubt, have the transmission flushed and add the above mentioned oil. Saving a 100 dollars on transmission oil for something which can cost you thousands to fix ( the transmission) does not make sense.Bill Russell, answerer above, says not to flush the transmission but if you do not then you will be mixing oils or even their residues which is not recommended.