Mopar Forums - 727 won’t work....grrrr

Hoping for some helpful advice....have a ‘68 Sport Satellite that I benched a few years ago to build. It now has a 440/727 combo, had tranny built (stock, no shift kit) by the local shop here in Missouri. Once installed and engine fired, tranny wouldn’t shift enough to drive around the block....fluid level okay, checked in neutral when warm. Trans pan gasket start leaking, so I replaced the cork gasket from the tranny shop with the Mopar rubber gasket and refilled with 3 quarts fluid as recommended. Had to keep adding and adding fluid for the thing to finally register on the dipstick, still wouldn’t shift into gear properly...move the column shifter into PRN123 and wiggle around until it caught, then would fall out of gear. Jacked car up and checked linkage adjustment....seemed okay. The next morning the shop floor is covered in ATF as the trans puked its guts of excess fluid, I guess....checked the fluid level after mopping up the mess and it’s right at the full mark. Started the car and it won’t shift into any gear. The only thing I can do is take it back to the tranny shop ( major hassle), but was wondering if there was any advice on something to check, or something I missed. Thank you