Is There A Sidewinder Pin Box That Replaces The Leland AF 7921 Pin Box?

Question

Question:

Looking to get a sidewinder due to having a 2019 Ram 3500 Megacab 61/2 ft bed with Ram boxes. Have a 2006 KZ Durango 5th wheel with a Leland AF 7921 pin box. Found that I need the ST400 turret to fit this pin box but am having a hard time finding that adapter.

asked by: Brandon T

0

Leland AF 7921 pin box
(click to enlarge)

Expert Reply:

Hello Brandon, thanks for reaching out. Sadly, there is no sidewinder that will replace the Leland AF 7921 pin box. The only pin boxes we carry that replace it are cushioned pin boxes like the Trailair Air Ride 5th Wheel King Pin # UF35-946208 or the MORryde Cushioned 5th Wheel Pin Box # MR52VR. With there being no sidewinder options, there really is not a good way to pull your 5th wheel with a tuck with Ramboxes. The only thing to do would be to get a different 5th wheel, or to convert your Rambox bed to the standard bed.

The ST400 turret you mentioned is unfortunately discontinued. We sold our last one about 2 years ago and we will not be getting more stock. So unless you can find one secondhand you will have to go in a different direction here.

expert reply by: Jesse M

0

Jesse M.

12/22/2025

Hey Brandon, what direction did you end up going after learning the ST400 turret was discontinued? Knowing how you handled the setup with your Ram and Durango could really help others facing the same challenge.

Brandon T.

1/1/2026

@JesseM I didn’t really find a good solution but we found a work around. I removed the bed rails in the inside of the bed to allow more clearance. I also set the BW hitch to the higher setting and am towing nose high but that has given me enough turning radius to back into all the spots we have stayed at. Would like to raise the back end of the camper at some point to compensate but haven’t found the best way to do that yet without adding a whole subframe.

Jesse M.

1/2/2026

@BrandonT Ok nice thanks for sharing! Good call removing the bed rails and raising the height setting on the hitch. As far as raising the back end of the camper, it can be done. The best way to do this is with a lift kit like the Correct Track Trailer Alignment and Lift Kit # RR23QX. This adds 1-1/4" of lift to a tandem axle double-eye leaf spring setup. About how much lift would you say you need to level things out?

Brandon T.

1/2/2026

@JesseM I have looked at that lift kit and it would definitely help but to be completely level it would need about 4”

See All (4) Replies to Jesse M. ∨

Answer 1

We do have a Sidewinder pin box that will replace the Leland 7921 you have on your 2006 Jayco with the part #ST400-5AS16K which is cushioned to improve ride quality. This will give you additional turning clearance and will allow you to not need to…

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Answer 2

None of the Reese Goose Box models fit the Leland AF-7921 pin box wings/flanges, but there is another solution. There are only two king pins that fit the Leland bolt pattern, those being the Trailair #UF35-946208 5th wheel kingpin and the Reese…

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Answer 3

I was able reach out to my contact at Reese and come up with some dimensions on the 5th Airborne Sidewinder #RP61422, but he was not able to provide me with complete measurements on this. However, he did say that this is an exact replacement of a…

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Answer 4

We have exactly what you are needing to give you additional clearance for your short bed truck! The Reese Sidewinder moves the pivot point of the trailer from the king pin to the turret of the pin box which will give you an additional 22 inches of…

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Answer 5

The manufacturer and model number of the pin box is usually printed on a sticker or stamped into a plate or directly into the metal of the pin box. If you can't find that, the manufacturer of your 5th wheel should be able to tell you which pin…

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Answer 6

In order to determine the torque rating for the lug nuts on your trailer you will need to know check out the chart I attached that shows all of the torque specs for all the trailer lugs available based on stud size, wheel material and wheel size.

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Answer 7

The OEM prep package consists of 4 "pucks" in the bed of the truck that will allow you to drop in puck style hitches for easy installation and removal, that gives you a completely clear bed when not in use. The B&W Companion OEM 5th…

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Answer 9

You will have to go with a sliding hitch to allow the trailer to make tight turns. For a trailer 8 feet wide the only bed length that's going to allow 90 degree turns without a slider is a stationary hitch. That being said you have two options.…

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Answer 10

Yes, it will work. You'll just need to cut the Lance 6-pin connector out and rewire it into the etrailer Trailer Wiring 7-Way Upgrade Kit w/ Junction Box and RV Style Connector item #e99011. Here are the individual functions of that Lance 6-pin:…

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Answer 11

Since the pin weight of your camper is 2.1k, I recommend going with the LoadLifter 5000 opposed to the 7500. While technically there is not reason you couldn't use the 7500 kit, it really is not necessary for a camper like yours. Generally the…

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Answer 12

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Is There A Sidewinder Pin Box That Replaces The Leland AF 7921 Pin Box?

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