I'd change it. There's no filter in the 850's tranny system, that's why they recommend changing it every 30,000 miles. The factory method is to do the initial drain thru the drainplug and refill with fresh fluid, then disconnect the aft line on the passenger side of the tranny and stick that removed hose end in a container, then crank the engine up and let it pump the old fluid that was in the internals of the tranny and converter into that container. Then refill the tranny again and repeat till clean fluid starts coming out of the hose, then top off the tranny and reattach the line. You can mix Mobil One synthetic fluid with regular Dexron fluid but if you are gonna do the flush deal just use synthetic. You might also look at installing one of those Magnafine inline filters while your at it.
http://emergingent.com/subpage1Magnefine.htm


Mike
'95 850T