I was just out putting a little bit of slick 50 tranny fluid in my 87 GN and i was letting the car warm up. After about five minutes, a light grey exhaust started to come out of the pipes. It is 50 degrees out, so i wasnt worried until about 5 min later when i noticed the exhaust getting darker (for reference, it was the color of GN seats plus a shade or two darker. There was no smoke or anything under my hood and no weird smells. The exhaust smelled normal too (not that i go around sniffing my exhaust to get high). When i revved my car, the exhaust went completely clear but when it went back to idle for 3-5 seconds, it went back to the same thing. It didnt seem like smoke because it didnt rise, or stay together as a cloud as it went out the garage door. I just dont want to screw anything up with it, and im paranoid as all hell. Any input would be great. Thanks.