Replace Lippert 1621HD kingpin


I have a 2019 Heartland EL 3760 which I am pulling with a 2018 Ram 2500, diesel, 6 1/2 foot bed. I recently replaced the OEM Lippert 1621HD pin box with a (supposedly compatible) Moyrde 1621HD rubber pin box for a smoother ride and less chucking. First time out, I made a sharp right turn and crunched the right rear pillar on my pickup and slight damage to the RV unit. I thought this was just a fluke and I turned too tightly. This last trip in July same scenario, right turn crunched same spot on truck and RV. Spoke to Moryde technicians and sales people, Amazon personnel where I bought it and they all say this fits my RV and truck. It appears that the RV is just contacting the truck by about an inch or so, rather than missing. It's very close. The original pin box by Lippert never gave me a problem, but it provides for a rougher ride. The RV dealer said I probably need a slider hitch and the local RV repair shop is looking at a slightly longer pin box.

Does anyone have any ideas, suggestions,or have had similar experiences.
Appreciate any help I can get.

Thanks, Jakenbear
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Well-known member
My first thought is that you would be required to have a slider. I have the 8 foot bed on my RAM. Not that I do this, but w/o a slider, if I turn 90 degrees the cap is so wide it barely misses the cabs back corner. Since you were lucky to have just gotten by with the stock pin box, might have been a fluke.


Get a slider (Pull-Rite) and your problems will be behind you. We have had the Mor/ryde Pin Box for 6 years and really like it, a big improvement from the conventional pin box. Our truck bed is 6.8 feet and without the slider, we would crunch every time.

Bobby A

Well-known member
Several years ago I had a pin box called a Sidewinder, its longer than the original and you don't need a slider hitch. You might see if they still make them.


B and B
I have a sidewinder on my Landmark. No problems in tight Provincial Parks with trees to dodge and tight sites to back 38 ft into.


Just a final note to my previous post. I ended up putting the original Lippert 1621HD pin box back on. After several hours of troubleshooting, we discovered that the rubber pin box by Moryde, even though it is the same dimensions, will move horizontally 2-3 inches when making a sharp turn. While driving straight or backing up straight, it works fine, absorbing any shock through the pistons and rubber molding, however, when in a tight turn situation it moves back, resulting in the RV getting too close to the truck rear pillar and therefore crunching both.

FYI I have a 2019 Heartland Big Horn 3760EL, pulling with a 2018 Ram 2500, with a 6 1/2 foot bed. Now I have a almost brand new rubber pin box that I can't use. I will probably put it on Craigs list or such. If anyone else has a similar setup and plan on switching out pin boxes, I would suggest they research it thoroughly to prevent having the same experience I did.


Well-known member
Your fifth wheel hitch may have adjustments that allow rearward adjustment. I had to adjust my B&W Companion hitch. The adjustment provided more clearance. But it is still possible for the front cap of the Bighorn to touch the truck at extreme turning angles. One more thing for my backing spotter to watch for.


Well-known member
have 2017 3760 el short bed chevy and have not had issues - have the more-ryde pin box from factory - when yours hit was it at a anlge/off camber? - I have b&w hitch ( non-slider ) and frequently have to back into tight quarters at race tracks and state parks