I am one of those guys who thinks that doing an engine oil change and not installing a new oil filter just shortcuts the purpose of the process. I see the goal as removing contaminants from the engine rather than from the oil and then storing them in a filter. In the case of an engine oil filter, a filter change is cheap and easy.
This whole business of flushing trannies I just do not understand. It lends itself very well to near fool proof tranny oil changes but it is not clear to me that the goal is achieved - that is removal of contaminants from the tranny.
If you believe ZF, the 6HP26X is supposed to have some sort of exotic oil poured back in. While the formulation is secret, I gather it must contain stardust as it it priced that way. Regardless, it is not clear to me that all the oil you end up with in the flushing process is the stardust oil and not oil from the previous tranny that was flushed.
Also removal of the pan allows one to look at the two magnets and see what is sticking to them. The consistency of the paste or size of the chunks that adhere to the magnets gives you a clue to what is going on with the hard parts.
Also the oil you drain out you can look at and you know where it came from. The colour, taste, feel and smell of what comes out tells a story.
Once you have gone to the effort of pulling the pan, a new filter is of course a given. That is why the metal pan option has great value. It makes pulling the pan more Chevrolet like and less German.
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