^Yes you are right - - never going to figure gearing out at 2:30 AM ever again
My mistake was saying that with no throttle change the revs on the engine would jump to 5000 rpm from 3000 on shifting - in fact it'd stay at about 3000, so with the gear downshift the driveline would suddenly be rotating more slowly, too slowly for the speed the car was rolling, and the tires would chirp.