What is the relationship between oil viscosity and engagement time period?
Lock-up of the MD is a function of the strut end angles and the notch plate and pocket plate geometries. The strut is forced into engagement by the torque load at the instant of lock-up, so the lock-up function and the effective time of lock-up are independent of oil viscosity over a broad range. Low temperature testing has been carried out and shows that the MD fails to engage at temperatures where the oil viscosity is very high (nearly solid). The failure to engage temperature was -43F for ATF and -65F for helicopter transmission oil.
