Alright so I found a bottle of honda auto fluid and since my tranny fluid was low I decided to add some in. What I didnt know was that someone put engine oil in that bottle. So as I poured the bottle in I realized it was engine oil. I think I put like a 5-10mL in. What would this do to my transmission?

 

5 mL(milli-liters) is about one teaspoonful. One or two teaspoonfuls of motor oil in your transmission more than likely will have no deleterious affect much less any noticable effect, I wouldn't sweat it.
In the future I would carefully consider using fluid you "found", that may be penny wise and pound foolish.

 

when was the last time you got your trans fluid changed? if it's almost time to get it serviced i'd go ahead and get your fluid changed with Honda ATF ... i wouldn't know if the oil would harm it or not but in my opinion its alot cheaper to change your ATF than to change/rebuild your trans.

 

thx for the replies. Yeah i will definitely check next time.