Good luck with the repairs. Hopefully your trans builder will sort out the trouble. It sucks when each one blames the other, and neither one can figure it out. Hope that's not where you're at. If you were closer, I'd be glad to help.
2001 ECSB 4x4, 5.3, Radix, 3.0 pulley, VHP Trucker cam, 216/224 .551/.551 115 lsa, 1.8 Crane roller rockers, 4L65E, Yank SC3000, 3.73, Cal-Tracs, HPTuners.