Hey forum, I really need some help.
I have a 2001 Subaru Legacy GT Limited Type S (automatic)

The background:
I took my car to Purrfect Auto to JUST have an oil change performed on 6/18/04. However, I ended up leaving with not only an oil change, but also having a transmission service performed (since I could not remember the last time I had had it done) and my air filter changed (it was dirty) for a grand total of $110.

Present Situation:
When I left the shop I noticed that my car sounded quite differently. Prior to getting these services done my car sounded much quieter than it currently does when I hit the pedal. However, now I would compare my exhaust to that of a modified exhaust a la a modified Honda.

I took it back to the shop this morning (6/24/04) and they said that they COULD NOT hear anything. I was pretty perplexed since the noise was obvious to my entire family, girlfriend, and neighbors last night. I argued with them for another 4 minutes until I got fed up and just left. They checked the tranmission fluid level, engine, and supposedly (because they did not lift my car) checked the muffler and said that all was fine.

I have had a few people drive my car who have driven it before and they too noticed that it sounds much louder and when accelerated at an increased rate (i.e. almost flooring it) it doesn't feel like it's getting the same amount of power as it had before.

We are all baffled as to what might have caused this increased noise. I truly don't mind the noise, but am worried about long-term effects this or anything related to it may have on my car. Any help would be beneficial.

Thanks

Specs:
Mileage: 33,000
Engine: 2.5 Liter, 4 cylinder
Everything in the car is stock.

Jack the car up and check it yourself. Or take it to a Subaru dealership. It's important that you have faith on the people who work on your car. It's unwise to take your car to Bob who have only worked on Inline 4 engine. If you going to take it to a shop make sure they have worked on box engine.

The only thing I can think of is that they needed to move the exaust pipe to get to the transmission, but Im not sure, ive never changed the transmission fluid on my car

I don't have a wagon. So I really don't know. But are there any exhaust pipe in the way of the Tranny pan? I don't remember any when I changed my tranny fluid.

Do you notice any driving differences?

After all this time, I'm sure your problem is corrected. But, this is my first visit here and here's my 2 cents worth on your problem. I have encountered the same thing with my 02 legacy sedan.

When they changed your air filter, they didn't get the box securely reassembled. If the box isn't reassembled correctly, you will get some strange looks at red lights (unless it's teenagers with their cars that sound like a mad bumble bee) and diminished acceleration. Check the air filter box, it can be a real pain in the wazoo to get pieced back together correctly but I feel that is where your problem lies.

Agree with comments on air filter. Had oil changed and immediately had low frequency rumble at high acceleration under load (when in gear). Found that air filter was installed incorrectly. They got all the clips to fit, but had not placed the bottom of the air filter side (inlet) inside the lower surface of the outlet side - resulting in large air gap.