Thanks for the advice duodeluxe. I will give it a try. I think that the ATF that fills the transmission is connected to the differential. I do not see that these are filled separately although there is a plug on the top of the differential. I mention this only to suggest that I should recheck the ATF level in case this fluid redistributed in the system and the transmission is now low. I will take a look.

I also did replace the carburetor so your suggestion about the carb could also be spot on. Sound like I should not sell the old girl quite yet :)