You put something else besides transmission fluid into your automatic trans? Like say... a fuel injector cleaner or somthing... in addition to the trans fluid.

 

FI cleaner? Nothing good will happen, that's for sure. Only bad.

I'd flush the trans and lines right away, unless you haven't even started the car since you did this. Then you might be able to get away with just draining the pan and changing the filter....

 

I used to put isopropyl alcohol into an old GM beater I had, to keep it from slipping when cold, and to get reverse to work (I think it was that crappy TH-200 in a 85 Olds) - when the alcohol evaporated and it started to slip I added more... Worked for a few months before I sold the car - and yes, I did say tranny needed work!

Other than that, ATF is a hydraulic fluid (basically) so aside from other ATFs ( and there are other major incompatibilities in them, too!) you run the gamut from just crappy performance to destruction of seals and eventual complete destruction of unit...