Whether it is a manual transmission or an automatic transmission you should use Dexron 3 available at most auto supply stores.
dextron 3
transmission fluid almost always goes in the dipstick tube
The transmission level is checked with a dipstick and not just a cap. Are you sure you are checking transmission fluid? Look in your owners manual. Some GM models also have a sealed for life transmission with no way of checking fluid level.
Mercon 3
Valvoline MaxLife Synthetic Transmission Fluid
6 quarts transmission fluid
Yes it could. If you put power steering fluid in the transmission you need to change the transmission fluid.
How do i check the transmission fluid in a manual 99 Hyundai Accent?
The transmission uses ATF+4.
The same place the transmission fluid dipstick is. Be sure that you actually need to add fluid or you can cause serious damage to your transmission.
Mercon v
Automatic: It is located above the transmission fluid filter on the front of the transmission. Manual: There is no Transmission fluid trmperature sensor for the Manual transaxle