"pghsprings" wrote;
I just looked at my 92 Loyale auto and it has a modulator valve.
There is a metal and rubber hose that goes from the top of the engine to the transmission modulator valve. I live in the forrest and the squirrels (sometimes mice) like to eat the rubber parts, especially vacuum hoses, for breakfast when a car sits in the same place for very long. With only 21K miles on yours, I assume it sits a lot. .
Without a vacuum supply to the modulator valve, the transmission will not shift. The hose can also be easily knocked off from the top of the engine accidentally. I would assume that if the Suby mechanic checked it at all, he might have missed a bit sized morsel missing from the modulator valve hose.
The hose is totally visible from the top of the engine compartment and goes down to the transmission on the passenger side along beside a pair of wires on mine. Then up to the top of the engine close to the front of the engine.. I assume you have checked all the normal things like fluid levels and the like. Of course, the rubber hose could just have gone bad after
14 years as well.Good luck and let us know if that was it. We have more ideas.
Almost any mechanic of any kind of car will know what a modulator valve is and can check that hose for you.
The Ole' Rep (not Subaru)
P.S. If they replace your transmission, can I have your old one?