Torque converter is directly in front of the transmission pan, there is a little "grate" for lack of a better word for it, that it is behind. You may or may not need to turn the engine over to see the drain plug in it. You can get to it easily through the grate. I don't know about the ATF change with that kind of miles, I wouldn't think it would hurt but wait for others to answer would be my recomendation.

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1985 300D Turbo ~225k
2000 F350 (Powerstroke) 4X4, SWB, CC, SRW, 6spd ~148k
1999 International 4900, DT466e (250hp/660 ft/lbs), Allison MD3060 ~73k