Ok i have to chime in here. Both putting the cooler before and after the radiator can be correct for a given situation. The only way to determine where to put it is to use a trans temp sensor on the output side of the transmission to monitor the temp of the trans.The average for the aw4 should be between 150- 170. This is the optimum temp (according to the fsm i may be off a little). Does it always run at those temps no. Depending on vehc configuration, drivetrain load and the way you drive it can be higher (i've never seen it lower). The transmission needs to run at temp of 170 or so for many reasons the two main ones are that is the temp the fluid was formulated to operate at the other is that if the fluid is too cold below 150 it is not hot enough to burn out the moisture in the transmission that accumulates when the vehc is cooling down. If you run the cooler after the radiator depending on the size of the cooler the temps can actually get to cold and drop below 150. Of course this depends on ambient air temp. If you live in an area where the year round temp is warm this is not usually a problem. If you live somewhere that's warm in the summer but cold in the winter the chance of overcooling the transmission is possible in the colder months. Running the cooler before the radiator is the safest bet. Which is why most but not all manufactures run it that way. In this configuration any overcooling done by the external cooler can be countered by the hotter coolant in the radiator as it passes through the heat exchanger in the radiator. Bottom line always test get a transmission temp sensor look at the gauge you may not need a cooler (but you probably will) decide what configuration is best for you and the climate you live in and run it.