LUBEGARD vs LUCAS for Transmission shudder.

I have seen several suggestions to add LUBEGARD to a Town Car transmission but I have heard of another product by Lucas. I would appreciate any opinions as to which may be better. My 95 Town Car suddenly developed a
shudder at 25-38 mph when cruising on a level road. I am hoping this is a result of my rinsing the top of engine with citrus based cleaner and water. Just in case I and starting to replace the transmission fluid an liter or so a day using a fluid transfer pump. If the problem clears up then I will drop pan and replace filter as well as drain converter if I can figure out how.
Your expert advice would be appreciated.

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