already having problems, however, it is true that if the clutches are already metal to metal, the dirty fluid will provide the needed friction to keep it going. Save the old fluid if it makes you feel better. I have been using the 'special' specific fluid when under warranty, but my trans guy says that's BS to sell you expensive fluid. Depending on how hard it gets used or abused, change the fluid often and you will get close to a 100% exchange. Actually, a lot of modern transmissions do not even have a filter anymore as I found out when I had a transmission fluid change on my 07 Saturn Aura XR (6 Speed auto)at 100k. A Lot of shops advertise a trans flush, don't know what the real difference is other than giving the impression that a 'flush' does more than a 'change' That is absolutely untrue. The 6T70 transmission in that car definitely has a filter. I know, I worked on that trans at GM and pulled apart a lot of them. The problem is, the trans has to come out of the car to change the filter. I have a 2008 Pontiac g6 and a 2010 Dodge Grand Caravan, both do not recommend fluid changes unless you are under severe service like police or taxi cab use or towing. In fact, the Grand Caravan has a dipstick that says "Dealer Only" on it, so you can't even check the level. Problem is, what does lifetime fluid