No offense taken. I was just trying to help the OP understand what would, and would not, work in his quest to change the oil more completely.
So, back to his problem, you and I agree - you can't get all of the old oil out, and the engine will run just fine, and last a long time, with a drain and fill and a new filter. Some engines are helped a bit by an oil extractor. Some are not (they really don't work on my Tundra or Mercedes, for example).
As far as transmission drain plugs - yeah, domestics gave up on them a while back. In the current fleet, I've got two NAG-1 (drainplugs), three AW-55s (drainplugs) an A750 (drain plug, but the fill plug is a complete PITA) and two manuals, both with drain plugs.
The AW-55s are the most problematic. The filter is internal, and it can't be replaced without removing the transmission and splitting the cases. I've added an external filter to those.
But hey, at least there is a drain plug, and a magnetic one at that, from the factory.
So, back to his problem, you and I agree - you can't get all of the old oil out, and the engine will run just fine, and last a long time, with a drain and fill and a new filter. Some engines are helped a bit by an oil extractor. Some are not (they really don't work on my Tundra or Mercedes, for example).
As far as transmission drain plugs - yeah, domestics gave up on them a while back. In the current fleet, I've got two NAG-1 (drainplugs), three AW-55s (drainplugs) an A750 (drain plug, but the fill plug is a complete PITA) and two manuals, both with drain plugs.
The AW-55s are the most problematic. The filter is internal, and it can't be replaced without removing the transmission and splitting the cases. I've added an external filter to those.
But hey, at least there is a drain plug, and a magnetic one at that, from the factory.