i dont know. i think when i flush my cooler it pumps in any gear and P with engine on
21. No movement in any gear: pump failure, or total loss of fluid. Remove transmission and rebuild, or refill pan and find the leak. If out of fluid, avoid running the engine until the transmission is refilled to avoid pump damage. To check for pump failure, check fluid level with the engine off, then start the engine and recheck fluid level. If level does not go down when engine is running, the pump is broken