I just put a pump bushing, input/output shaft seals, shift selector seal, and shift kit in my 4L85E. While the valve body was out, I also replaced the numerous filters and all the lip seals on the reverse piston, etc. I peaked in the front behind the pump, overdrive clutches and steels looked new, the seals I removed were in fantastic shape, pliable and no cracking. I considered rebuilding the unit, but what I could see was like new. After my little exploration dive, I found no reason to go into it deeper. Even the TCC and AFL filters were near spotless.