Dual Range Hydramatic Troubleshooting

longlivelance

I’m troubleshooting a hydramatic transmission I had rebuilt with the rebuilder right now. After installing it the car only barely crept forward in all gears including neutral and reverse. Below are the steps I’ve taken:

• Ran line pressure at the test port between the band adjustment screws and am getting zero pressure and the port is dry. I even tried cranking the engine with it open and no fluid. 
• After seeing that I wanted to verify my front pump was working and make sure the pressure regulator wasn’t sticking so I removed the pressure regulator and cranked the engine for a few seconds. Lots of fluid came out there. So it seems the pump is working. 
• I reinstalled the pressure regulator to try a line pressure test again hoping maybe the regulator wasn’t stuck. And am still getting zero pressure at the test port. 

The rebuilder is researching to see what they can find as am I. 

Has anyone had similar symptoms and if so, what was the cause? Any insight or advice is much appreciated.