Because they told me to change the fluids when I took possession of it. I was told that the transmission, differentials, engine and cooling fluid might be questionable. I was also told to change all the hose clamps out with stainless steel clamps so I did that also. Now I can assure you that it has mobile 1 75w-90w gear oil in the transmission and differentials. Mobile 1 10w30 in the engine along with a fram ultra oil filter and prestone antifreeze in the radiator.