On the 2ltr there is a drain plug [easy access] and a mini dip stick [ hidden down back of engine virtually inaccessible have to make up extension filler tube and extensionfor 2" dipstick and use probes to guide into filler hole] allow a fair amount of time and some calming down therapy. when I first changed my fluid the gearbox was performing fine but because I used it for towingthought it would not harm. when I dropped the fluid thought it was the engine oil, pure jet black !!!! .
must have caught it just in time, first thing changed the cooler not much bigger but more heat exchangersurface area went from a coil to a plate type. Secondthing fitted an extra in line filter with internal magnets . Third thing fitted a sensor and a gauge to give me a temp read out so I now know what is going on.
when draining, the coolers do drain, one in the radiator [helps warm the oil on start up] and one mounted in front of the radiator. so it is just the oil in the torque converter that is going to mix with the new. when I drain mine I get about 5ltrs out, can not remember total capacity. on my first change swopped the oil three times to get the colour back to something like. I had all four wheels in the air got the oil up to 65 degrees and went through the gears. Ichange the oil every year now just changed it this weekend but onlyone empty and fill no running through the gears, the colour is perfect. When filling to check the level oil has to be up to temperature and engine running.
Just a point about pressure cleaning the gearbox some people advise against it because any debris it removes can be left behind in places you do not want it, and prefer justto change the fluid.
Edited by: bel