Cross posting this here in case someone here can help...

Finally started my LSA 6L90E in my 69 Camaro and no reverse. Bought it all from Speartech including the E38 ECM, transmission, tap shifter, and gauges with gear display. All six forward gears work as tested with the car on a lift. Reverse doesn’t move but the display indicates it is in reverse. Fluid level is fine. Completely stumped. Transmission was a new rebuild and has zero miles.

Any ideas? Dreading pulling the transmission....

Don