on my 99 auto i put that dex-merc tranny fluid in and was wondering if that is good enough tranny fluid for it, and also is the transfer case supposed to have atf or gear oil in it???
also what mods can i do to possibly get 18mpg city and 23 highway, intake??? exhaust (what size)??? chip??? IS IT POSSIBLE??!!!

Thanks, Kyle

 

Dex/merc is perhaps the worst choice you could make for tranny. Did you read the applications? ATF 3 or ATF+4 would have been correct choices. You will find out eventually in shift quality. Suggest change two times to get most of dex out.
ATF 3 is fine for transfer case.
Drive as if egg under foot will get you there, assuming engine in good working order.