518 owners, What would be the average speed the OD would engage? Assuming flat grade and a nice even throttle. I am trying to establish some starting point to set my pressure switches and vacuum switch. I have a 95 518, using two pressure switches for OD and lock up and vacuum switch to disengage for acceleration. Thanks!

~40 & 45 mph is what my dad's rams engaged OD & lockup (not necessarily in that order, not sure which occured first)

My 94 diesel with I guess is a 46RH locks up at ~45 MPH. It's annoying, because that's the limit here on the highway, and it will hunt unlees it's on cruise. OD is higher, around 55- 60.
BTW, it won't start right now
https://board.moparts.org/ubbthreads/show...e=0#Post5848874

I haven't got the 1940 running yet, it has a 518.
The factory manual might have that info, but I don't have one here.

I thought it went into overdrive first and then locked up?
Or is this a chicken and the egg question?

With the truck, even with the OD off switch engaged, the lockup happens.
Different RPM drops will let you know....
OD (400-500 RPM) is a bigger drop than the lockup (100-200 RPM).