Answer
Apr 22, 2026 - 02:49 PM
This comes up quite a bit with the older HappiJac systems.
The Lippert 736514 (4220) and 736515 (4820) are both part of the newer generation of HappiJac jacks, while the 4500 series is an older design. Because of that, neither option is a direct plug-and-play replacement for a 4500 jack.
Between the two, the 4220 (736514) is the closer match and is typically the go-to when upgrading from older systems. The 4820 (736515) is a heavier-duty version and is usually only recommended for larger or heavier campers, so it’s generally more than what’s needed in most cases.
If you're just trying to replace a single jack on a 4500 system, the best route is to stick with a 4500 replacement if available. If those are no longer available, the 4220 is the better option—but you can expect that some modification or adjustment may be required for fitment.
If you're open to upgrading, the ideal setup would be switching all four jacks to the newer 4220 series rather than mixing old and new, as mixing can sometimes lead to uneven operation.
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