2007 f250 superduty diesel 212000 miles, minimally maintained. Truck shakes like going over 2x4s spaced every eleven feet at 1700 rpm of 4th gear. Doesn’t do it in other gears, doesn’t do it at higher rpm. No codes thrown on cheap Obd reader, transmission fluid looks ok, have not dropped pan yet. Motor mounts look ok.
Well I would assume there's some type of problem with that gear inside the transmission if it only does it Netgear at that speed
Will have a transmission shop look at it, thank you for your thoughts.
So it turns out it was the mother of all "transmission shudders", A lot better with two tubes of lubeguard transmission shudder from auto zone. has to do with the torque converter, not sure how long the fix will be temporized. Will search your site about transmission shudder, but if anyone would like to give me their experiences, that would be appreciated.