It was suggested that a transmission additive be used to help the shifting when taking off from a stop position. I was told that a transmission flush would most likely make it worse. After the additive was added, the transmission now will not shift. Do additives work as detergent or cleaner ? The only thing I can think that must have happened, is if that is the case, it freed up the built up grim and has stopped the flow of transmission fluid. Please help, as now I can not drive the car.
Most likely scenario your trans filter is now clogged. Drain the fluid, drop the pan and do the filter and keep your fingers crossed, after adding new transmission fluid of course.
Miracles in a can seldom are…
+1 with what Barkydog suggests.