.vtl wrote: ↑07 Jan 2024, 11:03I wrote it perhaps a zillion times here and in other Volvo forums, that heat exchanger gets only a small fraction of all ATF circulating in the system. Everything else goes back to sump. It is not like you take out 2 dirty quarts, put 2 fresh quarts and it never mixes with dirty ATF left in the system. Even if you drain the sump first and refill it with fresh ATF, doing the rest through heat exchanger does not prevent old/new ATF mixing up.MoVolvos wrote: ↑06 Jan 2024, 23:06 If you can drain the fluid through a plug in the pan and you empty 3.5 quarts, you'll wind up putting in fresh 3.5 quarts into the empty pan. Now, if you flush through the radiator transmission hose, all 3.5 quarts will be pumped into the system while 3.5 quarts come out of the hose.
There will be dripping from inside the pan but not 2 quarts. Have done so many of these on so many makes. I always flush through an extra 2 quarts of the system capacity but it's usually clean after the 1 extra quart.
When you say heat exchanger do you mean the compartment in the radiator where the transmission fluid is circulated to cool? The engine oil cooler gets a small portion of engine oil while the majority of goes through the oil filter but that's not case with the transmission fluid.
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