In the transmission?
the engine oil and trans oil is all in one!
You should use only Honda genuine transmission fluid. You can get a gallon of it at your local Honda dealer and change it yourself.
Same place you check the fluid level.
Only Honda ATF z1 fluid don't use anything beside that
3
atf z1 Honda
On top of the transmission under the air filter housing.
Use only Honda ATF Z1 and nothing else. Use any other fluid and you will experience shifting problems.
Honda recommends changing it at 100,000 miles. I personally recommend you change it every 75,000 miles. The 2003 Honda Accord had problems with the transmission so I would recommend this as a preventative measure.
Use only OEM Acura/Honda ATF DW-1 automatic transmission fluid. Do not use any other fluid that claims to be compatible.
You add fluid the same place you check the fluid level.
Honda Element was created in 2003.