My first rebuild using NIcks and Hiram's videos. I finished up installing all the components and the pump won't drop the last .25". I thought the forward clutch hub wasn't engaging all the clutches but that wasn't the issue. It looks like the Main Shaft is sitting to high. The Main Shafts lifting groove is .25" above the Sun Gear Shaft, in assembly video's I've been watching that groove very close to the Sun Gear Shaft. I installed a no walk case bushing and the rear endplay was .008.

I completely dismantled to assemblies and reassembled with only the Main Shaft with the Center Support, Direct Clutch and Output Carrier, I balanced on top of that Turbine Shaft Overrun Clutch and Overdrive Carrier. The surface that the pump thrust washer contacts is basically flush with the pump mounting face of the case.

I am at a loss as to what is causing this issue, except maybe the main shaft is an aftermarket part. I discovered this transmission had a TCI 2.97/1.51 first and second gear parts installed ( that was discussed in another thread). I purchased stock parts for the rebuild but a main shaft wasn't one of the part replaced.
Love to hear your thoughts. Thanks