Hi Dennis, You are in Virginia correct? I'm in Annapolis. Emf will burn the automatic computer and there is a chance of the unit failing. When the D is shifting up from 1st thru 3rd it is safe. When the D is downshifting from 3rd to 1st it makes huge electrical spikes in voltage...based on what I have be told. The device eliminates the spikes and makes the transmission shift smoother. There are several people who use the device. It is about the size of a 1" cube, and fits on the harness for the computer in the engine bay. They are reporting smoother shifting and longer life of the computer. A guy had 120,000 miles on his automatic at the last door adjustment. I have a schematic on how to build the device along with a parts list. I want the owner/inventor to contact me so that we can make a batch for the cars. Interested? Sincerely, Mike