I have seen quite alot of detailed discussions where most of the auto trans shifting issues are related to vacuum adjustments or replacing hoses to snug-up the system and/or adjusting the modulator . I have a 1980 240D, (don't have the trans # handy) that shifts fine, (tight, no flaring or slipping, no hard shifts, proper shift points, etc) for the first few miles and even longer when moving. However, if I am stuck in Chicago's stop & go traffic for more than 5 or 10 minutes, there is a pronounced flare between 1st & 2nd and 2nd to 3rd. WOT seems to over-ride this, as it should if the vacuum is adjusted properly. If I stop somewhere and let it cool-down for 20 minutes or so, it's fine again. Coming down from long freeway cruises into traffic causes no issues either, even though the trans and fluid are plenty warmed-up. Almost as if the trans is "air-cooled" and overheats in slow traffic. Is there a trans cooler by the radiator and if so, could there be a blockage there? Any other thoughts?