Transmission Gear Slipping problems of the 2008 Ford F-350

I noticed a plum of white smoke out the tail pipe. That indicated steam, water in the system to me. All the gauges were normal and I stopped the vehicle and checked the fluid levels. No obvious problem. I called my local Ford dealership and they could not get it in for 36 hours. I drove it . 4 miles home and parked it. At the appointed time I drove to north country Ford. It took them another day to find the diesel mechanic who could work on the vehicle. 24 hours later I am told the engine is blown; fluid got into the manifold and was sucked into the # 3 cylinder. Depending on the amount of parts that could be salvaged the cost of replacement could exceed $ 12,000. This vehicle has 95,000 miles on it. It has had tow other incidents with the engine and drive train: in December of last year, in preparation for a trip to arizona I had the transmission serviced. About 1400 miles later the transmission began to slip when we encountered any hills or mountains. I parked the trailer and took the tuck to cassa Ford. They had the truck for 4 days and $ 1600. 00 worth of repairs. I asked if anything done at the time it was service or the driving from the first sign of trouble had caused or exacerbated the problem. They said no, it was a pump problem. In 2011, it began to blow black smoke out the tailpipe; the dash screen indicated it was cleaning the exhaust. Within 5 minutes the engine sputtered and died. I called Ford I was told to wait an hour and try to restart the vehicle; give the engine an opportunity to ¿re-set¿ itself. That didn¿t work! a tow was sent and the vehicle towed to nelson Ford dealer in fergus falls, minnesota. It was a failed egr valve. The repair was covered under warranty.