i hooked up my rangie 1999 4.6 hse to the comp to fiqure out why the service engine soon light came on. the print out told me that there was a fourth gear fault. it directed me to add tranny fluid. now my question is where to i check the tranny fluid and where do i add the fluid if i need to?????????? please help

 

If you got a 4th gear out of ratio code, that is not always what it says. It could be low fluid or it could be the beginning indication of your MAF starting to fail.
How long has it been since you serviced your tranny? To check the fluid you have to start the engine, keep it in park and crawl under the tranny, remove the fill plu on the pan, if fluid comes out you are full if not you need to add some. If you are low, consider changing the oil, a filter is not needed.