Too late to change fluid?

If you're worried that by putting new transmission fluid in the car, the detergents will clean out the transmission and eat up the old warn seals and cause leaks, I would check the transmission fluid by the dipstick a couple of times. Start the car up, let the fluid circulate, then, check it again. If there's any metal grit in the fluid on the dipstick, its fugged. If it appears to just be dirty or old, go ahead and change it. I do recommend running full synthetic at this point. The car should of come stock with Mercon V which is synthetic blend. Lets just hope the previous owner knew all of this.

If thats the way it appeared on the dipstick, the fluid is going bad. Change it whenever you can and while your in there, change the tranny filter too. It's real easy to remove. When you drop the transmission pan, the filter will be starting you in the face. It just slides right out. No screws or bolts holding it in place.