How many miles on your X3? First time I hear about a GM5 tranny going bad in an X3. Good thing you had the warranty! Just take the car back to them, it's very common they don't get it right the first time around.
"If everything seems under control, you're just not going fast enough"
River City Bimmers Chapter
2005 X3 3.0i
ZPP, Htd seats, Htd strng, Black Sapphire on Terracotta.
1995 ///M3 Coupe
, Lux, MT, Htd seats, Cosmos Black on Black.