hi there 1979 cruiser with a alpha one and mercruiser 228 5.0 I think the previus owner never change the outdrive before I replace the water pump and the impeller on the lower unit, everything working fine but I drain my oil the other day and I find a lot of small metal particles in the oil what should I do send the upper unit for service or buy a new unit I been reading about sei drives they have a good price but what about their quality thanks again!!!