your transmition coler is part of the engine cooler the thermostate is in the top part of the water pump down where all the pullies are it is a devil to get to, i did mine , it was a case of droping the engine on that side .and the thermostate part is at the top with three bolts holding it in , and you also have the metal pipe that goes into it which runs around the back of the engine ,be carefull as the thermostate holder can break if you put too much presure on it , and are expensive from LR for what it is. hope this helps