Hi,
First of all I have a Disclaimer. I have no Volvo training, the following may be not be correct.
I have owned and serviced transmissions on euro things, eg. Q5/ Q7 with Aisin and ZF trans 5,6 and 8 speeds, VW's MB's, BMW's and others.
I used to go by the book with interfacing and reading temperatures and draining level plugs accurately.
Imho opinion the Volvo box is speced just above minimum as far as maximum engine torque load to allowable max trans torque numbers.
I have had it changed with VIDA previously.
When the trans is drained whilst hot the metal parts and the transmission case retain the heat and when it is refilled with new cold clean fluid the heat very quickly transfers to the new fluid. ( the thing to remember whether it be insulating something like your home or the fluid in the trans is: heat ALWAYS runs to cold and not the other way round.) Now because this trans does not have a filter, why? In this non filtered transmission fluid naturally free floats all the contaminants where everyone of the previously mentioned vehicles are fitted with replaceable filters which filter out much of the contaminants that are not filtered out in the Volvo.
Further as you may know the torque converter holds fluid that cannot be drained and is left to remix and contaminate your new fluid. One of the only exceptions that I can recall is Mercedes where many models have a drain plug on the converter.
To finish this long winded reply with the Volvo system the only way imvho that I am comfortable with is to do a 5 times flush where I drain about 4 litres when the drain plug is removed. I then put 4 litres back in and that brings me back to the height where the level check plug overflows. I do this 5 times ( 1x20 qtr drum, cheaper that way) and I do not worry too much about the trans temperature and just drain off at operating temp. I find it takes a 5 times flush to satisfy me the fluid is clear.
The Volvo not being fitted with a filter and a torque converter that cannot be drained needs a big flush.
With the other vehicles mentioned one just drains the fluid and replaces the filter then fills one time with new fluid .
I have done 200,000 + k's in the XC60 without any issues and the trans operates correctly.
One could check the expansion rate of fluid by degree in temp, I doubt in my ignorance that the expansion would be significant .
One could try it at home on the stove in a pot with 200ml of fluid and a thermometer. Might make the porridge a bit unpalatable though.
Hope I have been of some assistance.
?
