Purely for information in case anyone's reading and is curious about the end play specs... Front end play spec is .015-.035 for all 700R4s and 4L60Es; I shoot for .015-.020 on my builds as a tight case is a 'right' case. There's no rear end play spec for the 700r4/4L60e though you can shim the rear gear train to tighten up front end play. You can also shim the relationship between the front planet and output shaft to reduce travel of the output shaft at the front planet to reduce stress on the snap ring holding the output shaft in place at the front planet.
If front end play is too tight, parts will overheat and there's potential for a temporary, repetitive interference fit condition between pump, reverse input drum and forward drum as temps rise and fall and as the vehicle accelerates and decelerates moving parts back and forth. In extreme cases, this results in forward drum thrust bearing failure which, when it collapses, creates an excessive end play condition (sometimes as much as 1/4" of an inch). Needless to say, parts get damaged real quick, including both drums.
On the other hand, too much end play, e.g. .040+, the forward drum thrust bearing gets battered as the forward and reverse input drums move back and forth longitudinally between the pump and front gear train while the vehicle's transitioning from accel to decel, resulting in more parts damage.
