I have a 01 gt with a tr3650 with 130k on the clock I bought it about 6 months ago. I asked a ford tech about changing the tranny and differential fluid and he said it wasn't recommended because my car has so many miles that there are too many metals shaving in there.... Which was the same thing my grandfather said.... but for some reason I can't seem to understand that concept. Can some one educate me on this. I'm just trying to keep my car running right so if changing the fluid is not beneficial I won't do it but if it is I'm definitely changing it out.