New transmission, nothing!

[fostrem]

So i recently put in a freshly rebuilt th350 in my 76 k10. I primed the TQ, made sure the TQ could spin freely before bolting to flywheel, and still the transmission wont engage.
I initially put in 4 qt of fluid, ran through the gears, got no response. Then added another, and repeated. In total I added 7 qt plus the 1 I primed the TQ with and still Ive got not response in any gear.
The TQ is spinning just fine with the engine.

The dip stick will say full then once it is ran it will say empty, so I'm guessing the pump is working. Is there just not enough fluid to get pressure yet?

Any input would be greatly appreciated.

Thanks!

Edit: the transfercase is in drive, I double checked by removing the driveshaft.