1996 F53 Coachman Mirada

I have a 96 Coachman F53 Ford drivetrain, motor is a 46o transmission is an E40D, when I first start the coach up cold, the transmission takes approximately 30 to 60 seconds before it will shift into reverse or forward. Fluid is fine, and full, red color with no odor. After that initial delay it shifts fine the rest of the day, no slippage or any abnormalities at all. Every time that I restart it while it's warm, no hesitation at all, goes right into gear and shifts normal. Does anyone have any advice whatsoever on this please ? I sincerely thank you in advance and look forward to your reply !!!