Should be a threaded flared fitting
It doesn't make a lot of difference. The fluid is pumped out of the trans, through the cooling coil in the radiator's side tank, then back to the trans. I think from the factory they come upper to upper and lower to lower.
upper line on radiator connects to transmission front
== == If it is a automatic, there are cooling lines that run from the trans to the trans cooler, which is the lower part of the radiator. This allows the trans fluid to be cooled down and then sent back to the trans casing. The trans cooler is a miniature radiator, with fins that disperse the heat from the trans, to keep it running cool and happy. The trans fluid and the engine coolant don't mix, obviously. There is a line from the trans to the cooler, and another one that brings the cooled fluid back to the trans case. Don't disconnect this line while the engine is running, as it is under high pressure and will spray all over the place.
You will notice two lines going to your radiator from the transmission. One is a service line and one is a return line. The radiator has a transmission cooler built into it. If you have trans fluid in the radiator chances are the trans cooler is leaking. A little trans fluid in the radiator will not affect engine cooling BUT as soon as the pressure drops in that transmission you may very well have radiator coolant sucked into the tranmission and that will ruin a transmission in a hurry. You need to get this checked out as soon as possible.
BOTTOM
I'm trying to repair and replace my trans line on a 2002 Chevy trailblazer...i have already replace the front line that connects to the radiator..near the wheelwell it connects to the other line the connects to the topside if the transmission...i cant see where the connection is to remove the clip that holds the line in the trans..but i can feel it,but i can see no way....HELP !!
Remove the two piece rad shroud,remove fan and fan clutch. Remove both rad hoses, if you have a automatic trans you will need to remove the trans cooler lines. The rad will be easy to remove at this point. The hardest part can be removing the trans cooler lines; a quality flare nut wrench must be used because otherwise you will strip the hex off the line.
I have a 93 3.8 and it's not a bad project but the lower oil cooler line is a b..tch, disconnect the lower line from the two brackets under the radiator and install lower line before you install the radiator
02 Jeep Grand Cherokee 4.0 radiator removal: Total removal time: approx. 3 hours. Quick steps:remove/unscrew/unplug:Neg batt terminal, fan wire harness, upper rad hose, 8 bolts holding metal upper rad support, 3 lower screws holding grill, 3 upper screws holding grill, 2 spring clamps on trans lines underneath, CAREFULLY unscrew trans cooler line(upper)(line has fitting and threaded shaft with lock nut, remove just fitting!), remove both headlights, remove upper metal rad support, move rubber air defletors to gain access to 2 10mm rad bolts, access them thru grille opening, from bottom front, lift a/c condenser up off two lower slide in clips, lift up rad/fan/shroud assembly, remove 2 10mm bolts holding shroud, remove shroud/fan assembly, now remove lower trans cooler line, and lower rad hose, slightly bend a/c pressure sensor from passenger side line under upper hose, bend it maybe 8 degrees towards passenger side, now slide rad up and out. if threaded end is attached to trans line, vise grip threads and remove line/fitting combo. Total time start to finish is less than 3 hours.
Disconnect battery cable, thendrainengine coolant,remove air cleaner,remove upper radiator hose from water bypass tube, remove radiator overflow hose from radiator and fan shroud. Noteloosen transfer. Oil cooler lines while securely holding radiator connector with a back up wrench, remove transfer. Oil cooler line from oil cooler inlet fitting, remover nuts retaining A/C csondensor core to the radiator,disconnect engine control sensor airing from the auxillary elect. Cooling fan motors and the CCRM, raise vehicle on hoist, remove splash sheild from lower radiator support and front sub frame, remove lower radiator hose from radiator. Note: loosen transfer. Oil cooler limes while securely holding radiator Conn. With a back up wrench, remove oil transfer. Cooler line from cooler outlet fitting on radiator, remove retaining screws for power steering/transaxle oil cooler and position cooler aside, support fan shroud, radiator and A/C condensor core with a suitable jackstand. Remove lower rediator support. Position jackstand aside and carefully remove radiator and fan shroud, remove two retaining bolts for fan Sheldon at top of radiator and remove fan shroud from radiator, remove upper radiator hose from radiator. Reverse to install.
Although I am not familiar with the vehicle in question specifically, generally the line that goes to the top side of the radiator is the supply, and the line from the bottom of the radiator or trans cooler is the one returning the fluid to the trans.
Jack front up and block, so wheels can rotate. Remove lower trans line at radiator, place bucket under this line and run engine at idle till about 2 litres fluid comes out. Now re-connect line, lower vehicle, run engine at idle for 3-4 minutes then check levels with engine running. Adjust level if necessary.