Subaru loss of accelleration

I recently had an oil change done on my 99 Subaru Outback. I went to a shop that had just opened. Shortly after leving the shop, I smelled something that I can best describe as a sulfer smell. Also, had smoke coming from under the hood. Temperture gauge did not indicate that it was over heating. After a few days, I returned to the shop so that they could take a look at it. They discovered that the diff stick was not put back and that the fluid had been coming out, which is what the smoke and burning smell was from. They replaced the stick and said they would recheck all fluid levels. It has been 2 weeks since this oil change was done and ever since then, my car does not run the same. I have intermittent loss of power, followed by immediate accelleration. This seems to be getting worse. My question is…could the situation with the diff stick and loss of fluid be related to this problem?

Definitely yes. You need to have it examined by a good mechanic, describe exactly what happened. Click on ‘mechanics files’ above to find one in your area that specializes in Subarus, they’re different animals in some ways.

Draining the transmission final drive oil by mistake instead of the engine oil has been known to happen as the engine drain and the final drive drain plugs are similar and close to each other.
Transmissions have been wiped out because of this kind of error.

Is this an automatic transmission? Just asking, because the advice may vary even though the end result could be catastrophic in either case.
Was this stick a short one (12" or so) or much longer?

This is an automatic. I did not see the stick but I did see that the stick was located as far back as it could be. In other words, he was standing on the passanger side of the engine when he saw that the diff stick was not put back. The area where he picked it up from, was just underneath the windshield, so as far back from the front of the engine as it could be. Does that make sense?

With an automatic, there are 2 sticks on the transmission. One on the driver’s side of the car measures the auto transmission fluid (ATF) and the short stick on the passenger side measures the final drive gear oil.

The latter is the one affected if someone fumbles the football so to speak during an oil change and drains the final drive by mistake.
Usually if this happens there will be a whining sound (subtle or pronounced, depending) from the rear of the engine area.

I could also theorize here that the auto trans fluid stick was left out and the transmission puked out some ATF fluid. It doesn’t take much fluid loss in this area to cause transmission damage. This can lead to slippage and topping off the fluid along with replacing the stick after the fact may not accomplish much.

It might not be a bad idea to have a reputable independent transmission shop take a look at this; just in case.