4lo doesn't go

Hi, I searched for a similar issue I'm having but only found posts regarding the 4lo light blinking. Mine isn't. Here's the issue:

4hi engages normally. Trans in neutral, vehicle stopped, 4lo appears to engage normally. Actuator makes noise, '4lo' light comes on and stays on (does not blink, no beeping). After 4lo "engages" I put the trans in drive, or reverse, give it throttle, and nothing. The truck goes nowhere. I've lifted the truck and inspected the actuators. They seem fine. When I manually spin either the front or rear wheel, the opposite axle wheel moves (spin rear, front wheel moves, vice versa), so it seems like the t-case gears are engaged, but still no movement. No check engine light, and no codes. Any ideas?