Looking for some information on possible ways that my transmission fluid could have got contaminated during a service. The services was a 90 month or 150000km. The car has only done 85000km. In addition to the service the timing belt was replaced along with idler pulleys, tensioner, water pump and they sent the radiator away to have the top tank replaced due to a hairline crack in the top outlet pipe. Neither the radiator or water pump were leaking. How could contamination of the transmission fluid have occurred? Images of contaminated transmission fluid attached.