I have a 99 Ranger, extended cab with a 4 liter, automatic, 2 wheel drive. Sitting at a light for about 30 seconds and wham!, the truck feels like it was hit in the rear about 5 mph by another vehicle. No, I look and the car behind me is about 10 feet back. The transmission feels like it dropped into low and dropped hard while I am sitting there. After a few miles and a another stop light it happens again but not as hard.
Anybody experience anything like this? What is the remedy?
Note: Automatic transmission fluid transfusion was done about 2 months ago at 35,000 miles.
Any answers, theories or speculations will be welcome.