Parking brake will not disengage 2007 GS Sunvoyager

[tallen5333]

2007 Gulfstream Sunvoyager, with Freightliner chassis, Allison 5 speed trany and 300 Cummins FRED. When put in driving gear parking break will not disengage. "Brake" dash light flashes and alarm is sounding but will not disengage. I tried the manual disengage by going to drive gear, then neutral as the manual says but still not work. Help, I can't move my coach.
The leveling jacks are up, the slides are in so that's not the issue.

[teebee60]

Is the air pressure up when you try to disengage?

[tallen5333]

Not air brakes. Standard brakes.

[fanman]

I have the same rig as you and I've noticed a delay sometimes but after no more than 2 times of selecting D and back to Park it will engage. Did you find the problem with your rig? I could have the same problem down the road.