You have to turn the locking ping with the slanted side out or it won't go all the way in. Also, I have to install mine upside down (from the bottom) to have clearance on the base plate. Just my findings, others may vary.
2017 Phaeton 40IH XSH Maroon Coral - Power Glide Chassis with IFS
Previously '15 Tiffin Allegro RED 38QRA and '06 Itasca Sunrise 35A
'16 Jeep JKU Wrangler Sahara or '08 Honda Goldwing