I have a 1993 automatic RX-7 FD and I need some guidance. The car moves normally in Drive on flat ground, but when I try to go up a slope in Drive the engine bogs down and stalls. If I put it in Low (L), it climbs with no problem. The ATF level is correct and the car doesn’t slip on flat ground. Has anyone experienced this? I’m thinking it could be a shift solenoid or something in the valve body not providing enough pressure for 1st gear when in Drive.