need a professional diagnoses on 2005 Ford Escape Hybrid

3 months ago had shutdown at 45 mph when out of town. Saw me coming! Repaired for $550, (temp guage). got an hr down the road, same thing. Repair was $490 at a different Ford dealer, more honest, and replaced the part that keeps the battery from overheating. Now upon a hard acceleration (70-75 mph) engine made I loud reving or winding as if not to change gears or engine locking up. The triangle appeared, then engine slowed down with stop safely alert, I limped off the interstate to a parking lot. turned the engine off then restarted fine, although made a clicking sound with some vibration. I decided to chk oil, there was very little oil and brown sludge on the stick. HOW could this be?? Had oil changed at Valvoline rite before leaving for out of town. Vehicle has been to 2 dealerships since then. My vehicle has only put 3500 miles since the oil change. I use a synthetic blend. I do live in TN, lots of salt on roads in winter. When I had a friend tow the vehicle to his place to have a mechanic look at it, they saw no oil leakage, no smoke and when I first ckd after the incident the engine was completely cool. As a mechanic with a diagnostic machine that was for non-hybrids, he only got a code reading for ABS brakes.He found no leaks, oil looked good after 3 quarts that I put in, and air filter and oil filter looked clean and damage free. SO, took to Ford dealer. They just called and said Ford recommends a new engine when metal shavings are found. He said that they felt the engine was shot. I am not sure that I trust the diagnosis. I never had a ck engine lite or any symptoms whatsoever before the hard acceleration. I drive at the most .300 miles a week, and most weeks less than 200. Could this be the motor mounts. The worst of it is at speeds above 45mph, but after the incident , it still sounds different at idle. I cannot spend $6500 to replace motor, as I just don't have it.