During the first morning start my trans will make a whirring noise. The exact noise is the same as a 79 Ford van made that I owned back then. The noise back then was a transmission modulator.

IT will go away. Sometimes it last 10 seconds and sometimes it takes a bit of driving. Once the noise is gone, it will not appear again that day. Next morning it will be there.

I've suspected a dirty filter or a trans pump. I've changed the fluid three times this week, last fill was with synthetic. The next thing will be a back flush and then a new filter.

Shifts fine, no codes and flooring it will jerk your head off. I do notice that in the morning for a few moments, while turning around in my driveway, there is hesitation with gear changes.

Car is a 1990 XJ40 with around 185,000 miles on it.

I have never ever had good experiences at trans shops therefore I loath taking this car to a trans shop.

Ant ideas.