I have an '81 Fairmont sedan with a 200 I6 and a 3speed auto with 51,000 original miles. The tranny will shift very quickly into 3rd gear when you start moving almost skipping 2nd, and not holding 1st long enough either even if your speed doesn't warrant 3rd gear at all. This creates a gutless driving experience. All gears work fine if you shift manually. Also the car won't downshift on it's own unless under extreme load, or stopped. Any help would be greatly appreciated, I really don't want to do a full rebuild if it's not necessary.
Thanks
Guy