Thanks for the replies guys!
You all sound like adding dexcool is as bad as using type IV liquid in transmission. What is the problem with Dexcool coolant? The reason I'm asking is because I topped up coolant with Prestone Dexcool approved 50/50 mix.

Hello, I have a 1.8l Pontiac Vibe 2010 with an automatic transmission. The car has about 92000 km on odometer and I think its about time to flush the transmission and replace oil in it. I took the car to the GM dealer to do a transmission flush and they told me they were out of Type IV fluid so they...