2004 chevy trailblazer_lt
So my tranny has always shifted well. The other day when i was getting onto the interstate i noticed that when shifting from 2 to 3rd it was revving high and not shifting until i let off the gas. When i got home i heard a clicking sound coming from under the car. When i drive slow the tranny shifts fine and it also shifts fine when i manually shift from 1 to drive with the shifter. Seems that in drive and at heavy throttle it dosnt want to shift correctly. Any thoughts on this would be greatly appreciated.