1979 Dodge Van Transmissions

I was wondering if any one knows if 1979 Dodge Vans had regular 727 transmissions, or 727 with lock ups? I was told that Chrysler switched to the lock-ups in mid year. Can anyone confirm this? I was also told that if you use a trans on a 318 that had a lock up it would cause a vibration in the drive train at high speeds, and might damage seals in the engine and trans. Can anyone tell me if this is true? Thanks Phil.

I don’t remember the 727 having a lock up. The 904 did, don’t know of any problems with it, but most American made cars had problems in the late 70"s through mid 80’s. They weren’t ready for the emissions laws.