No question (I had asked some time ago without getting a reply) but a recommendation for other new 850 automatic transmission owners. I bought mine with 210.000 km, 10 years old, well serviced but without ATF change. Volvo recommends no change for lifetime except under hard conditions (like city taxi driving change every 75.000km). I had the problem of hard noisy shifting from
3-4 while the lower changes went smoothly. Today the oil was changed and miraculously the shift 3-4 is practically as smoothe as the other ones. My mechanic told me that a lot of "mud" came out with the old oil. Why did Volvo not recommend regular oil change in this automatic transaxle for the whole lifetime? Either they overestimated the properties of the oils? Did they underestimate the lifetime of their cars? Did they have a large unused stock of transaxles on stock they wanted to sell? Who knows....Anyway I am relieved apparently no costly gearbox repair is threatening and recommend everybody with this gearbox to change the oil regularly contrary to what is recommended by the Volvo service plan. The ATF costs 5 Euros/l at my mechanic. Changing 10 l every 30.000 km is a 150 Euros/90.000 km - a tiny fraction of what a gearbox repair would cost.
Regards Viktor