Oil was appearing into radiator overflow reservoir. I changed the radiator fluid twice, and flushed. Problem was not solved so I had it looked at. Engine oil was not frothy so we knew it was not a head gasket. Then we checked the transmission fluid, I was down a quart. We then knew it was a hard pressure line into the radiator that cools the transmission fliud. Bought a new radiator, and ever since had no oil in the reservoir.