A 1998 Oldsmobile 88 takes ATP automatic transmission fluid. This is sold in most places that carry transmission fluid, or you can buy it through a dealer.
4-4.2Litres
Transmission lube goes in on the side of the transmission under the car.
it goes in the dip stick tube.
AF
if the transmission does not have a dip stick it is probably atf
You check and add fluid at the same place.
Dextron/Mercon III will work for that transmission
When changing the transmission fluid and filter of a car, it is best to know how much transmission fluid goes back into the car. The 1998 Bravada takes close to 12 quarts of transmission fluid to fill.
V.W. recomends you use d.o.t. 3 brake fluid
The 1998 Ford Taurus Owner Guide shows : Motorcraft MERCON - V , automatic transmission fluid For the AX4N and AX4S automatic transaxles
the part of the transmission where the fluid goes is on the drivers side part of the transmission. its right above the transmission temperature sensor and its the biggest bolt head right above the transmission temp sensor