Trans cooler is IN the radiator, on the passenger side. If you have the tow package, you will have an additional cooler between the radiator, and A/C condenser. To flush 'em, just run some manner of fluid thru it in both directions. Should be able to disconnect the lines right up by the radiator to clean 'em out.

 

were would I look to find this, and how would i do about flushing the radiator and the lines

 

pass side... there will be two smaller hoses running into and out of the radiator... one will have a check ball... you need a special tool to remove them.... after they are removed use an air compressor at low psi like 10-30psi and blow out the lines in both directions...replace lines and top off with fluid while idle in nutural