This is what the factory service manaual says about cooling for a 2000 - I think a 98 would be the same:
Transmission Cooling
All vehicles with automatic transmissions are equipped with integral transmission fluid coolers (7A095). The integral transmission fluid cooler is contained inside of the radiator outlet tank (8054) and cannot be repaired separately. All (AWD) vehicles are equipped with the transmission auxiliary fluid cooler (7K177) which is mounted in front of the radiator (8005). In operation, transmission fluid travels from the transmission to the integral transmission fluid cooler to the transmission auxiliary fluid cooler then back to the transmission. The integral transmission fluid cooler transfers heat from the transmission fluid to the engine coolant. The transmission auxiliary fluid cooler transfers heat from the transmission fluid to the outside air.
For transmission fluid cooler flow test, refer to «Section 307-01A» and «Section 307-01B».
For transmission fluid cooler backflushing and cleaning, refer to «Section 307-01A» and «Section 307-01B»
