727 no 3rd gear

Ok, I'll give this a shot. Many years ago I had this same problem on 2 different trannys. Sb 727 1-2 shift fine , reverse fine. Turned out it was the inner lip seal in the front drum. I know I know had me stumped for quite awhile. Tranny number 2. Bb727 in a truck. 1 of the 2 sealing rings on the rear of the front pump broke, losing pressure or I guess not being able to hold the pressure.these were my findings after many hours of head scratching and conferring with other wise men Kim