I only mention my older 300SD because it had hard shifting for a year and a half and then something broke inside and I wasn't sure if it was related to the vacuum modulator being disconnected for all that time. I wouldn't want to disconnect a vital part that would cause the transmission to get damaged on my running 300SD.

Is there information somewhere about the vacuum adjustments to minimize the flaring?

I only mentioned my two cars because the issues seem related.

I actually live in New Jersey, I don't think it's nearly as cold as Canada, maybe it's been 35 deg at night lately, and the worst it gets is maybe 5 deg.