450 sl vibration and temperature higher than normal.

I replaced the head gaskets on my 450sl and bent valve. the engine runs beautifully now. So i decided to take it on a long trip after sitting all winter. after going about 200 miles and filling up with gas, I stopped at a red light for a long time to wait for traffic to clear and took off. The temperature had climbed to about 200 degrees. The car took off fine but when accelerating up a hill I notoced a vibration from underneath that got fairly stong. I pulled over and couldn't find anything. Transmission fluid o.k., no leaks no play in the wheel bearings or drive shaft but the transmission seemed not to want to catch in park. I continued my trip another 150 miles with an occasional vibration when the temperature would climb at red lights. On the way home another 350 miles I never felt the vibration again but notoced the brake squealing on the right rear without any pedal pressure. Could it be that my caliper was dragging causing all this or is it a separate issue, or do I need to flush my radiator and xmsn oil cooler? The transmission has only 56,000 miles with a fresh oil and filter change. Also the rotors never got hot and look fine.

Any advice would be appreciated,
thanks in advance
jmdunn