you may be right about it being overkill but you certainly don't need combustion in order for it to breakdown. Heat and frequent temp changes (as we have in the PacNW) can break down trans fluid. Same with the differential. Also, you can visually tell if the fluid is sludgy and gritty without it being substantially darker or dirty as you infer.
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'13 Individual Frozen Brilliant White ///M3 Coupe
Ordered 2/15/12 | Euro Delivery on 9/21/12 | U.S. Redelivery on 12/6/12 | Motor Dead on 7/15/13
'13 Space Gray/Mugello Red X5///M
Pavement Punisher | Snow Muncher | Family and Board Hauler | Roadtripper
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