98 grand prix . 3.8, no mods 212,000kms
when accelerating in town 0-50kms an hour it shifts fine from first to second, but when it should shift to 3, it shifts directly into 4th gear. . so when i step on the gas a little harder to accelerate after the failed 2nd 3rd shift, the car seems to bog a little , and i really have to stomp on the gas to get it to down shift. when it down shifts it goes right to 2nd, sometimes 3rd catches.
On the highway at 100kms an hour, same thing to get out to pass someone i have to really stomp on it to get it to shift down, and when it does it shfits very hard.
Anybody else had these problems ? Would a full trans flush be better than just a filter change? any recomended additives?