2005 S40 AWD transmission rough downshift when warm.

[atikovi]

I recently got this car which has 251,000 miles and the Carfax shows the transmission was overhauled by AAMCO at 205K. It was again serviced at 237K at AAMCO and at 250K it was serviced at another transmission shop before the car was traded in. I guess the owner didn’t like AAMCO anymore and the other shop had some bad enough news to make her get rid of it. Anyway, it has a harsh downshift from 3rd to 2nd when coming to a stop and when it’s warmed up. The whole car shakes as it clunks into 2nd gear. I don’t notice it when cold. I also hear a whistling noise under the hood I’m thinking might be vacuum leak. Any suggestions? Does this transmission have any vacuum controls?