I have a AT 1991 Legacy wagon. I have been having shuddering in the steering wheel at high speeds but then all symptoms stop, especially when at Dad’s for a look-see. Also, some hesitation going when cold and now it won’t go in drive at all. I managed to limp it to the parent’s house by putting manually into first gear, then second, etc, It would go OK until over 2,000 rpms then it would just rev but not go? Two separate problems or one? I read that one should check the transmission filter, can Dad do this or does it need to go to a shop for that?
The first thing to do whenever there is an issue with an automatic transmission is to check the transmission dipstick. Since you did not tell us the level, or the color, or the smell of the transmission fluid, I have to assume that you have not done this. If you don’t know how to do it (or even if you THINK that you know how to do it), consult the Owner’s Manual for a description of the proper procedure. After you have checked the fluid, come back to this thread (don’t start a new thread) and report your findings.
A transmission filter is not “checked”. The filter is changed at the same time as the fluid is changed, and on a Subaru transmission, these services should be done every 30,000 miles.
What happens if you don’t change the fluid and filter every 30K? The transmission will have a tendency to hesitate when cold, and to allow the engine to rev without the car moving. Does that sound familiar? Eventually, lack of transmission maintenance means overhauling/rebuilding/replacing the transmission to the tune of perhaps $2,000.
As to the shuddering of the steering wheel, that is more likely to be one or more imbalanced tires, but it could also be an indication of bad ball joints, or bad tie rod ends–both of which can lead to a really serious accident when a wheel separates from the rest of the car or you lose the ability to steer the car.
It sounds to me like this car needs some serious attention from a qualified mechanic (Note: That excludes any chain operations or tire shops), and you have to be prepared for repair costs that may well exceed the book value of this 18 year old car.