Updated Oct 31, 2021
Brachycrus moved to the astrapotheres here.

According to oreodont expert Meaghan Emily-Wetherell
(see YouTube video below) there are about five people on the planet interested in studying oreodonts (Merycoidodontoidea). IMHO she’s the enthusiastic one somewhere near the top of that list.

According to Wikipedia,
“Merycoidodontoidea, sometimes called “oreodonts” or “ruminating hogs”, is an extinct superfamily of prehistoric cud-chewing artiodactyls with short faces and fang-like canine teeth. As their name implies, some of the better known forms were generally hog-like, and the group has traditionally been placed within the Suina (pigs, peccaries and their ancestors), though some recent work suggests they may have been more closely related to camels (Spaulding et al 2009).”

By contrast
in the large reptile tree (LRT, 1901+ taxa; subset Fig. 2) oreodonts nest between the Phenacodus clade and the mesonychids, basal to hippos, desmostylians and mysticetes. And Brachycrus nests with South American astrapotheres. Evidently taxon exclusion is the reason why oreodonts keep getting nested with camels rather than phenacodontids and mesonychids. Hippos, as everyone suspects, are not artiodactyls. Unfortunately, professors still teach that at the university level. Adding taxa solves the issue.

Here’s the video.
I think you’ll find it delightful and informative. Evidently oreodonts were a scrappy bunch. Dr. Emily-Wetherell will make most viewers interested in the oreodont.

Missing from the video is a valid phylogenetic context.
Wetherell follows traditional thinking (see above) that oreodonts are close to camels within the Artiodactyla. Hopefully she will someday run an analysis that includes pertinent taxa recovered by the LRT (subset Fig. 2).

References
Emery MM, Davis EB, and Hopkins SSB 2016. Systematic reassessment of an agriochoerid oreodont from the Hancock Mammal Quarry, Clarno (Eocene, Duchesnean), Oregon. Journal of Vertebrate Paleontology 36.2: e1041970.
Schultz CB and Falkenbach CH 1968. The phylogeny of the oreodonts: parts 1 and 2. Bulletin of the American Museum of Natural History. 139: 1–498. hdl:2246/1992

meaghanwetherell.com/
ischool.arizona.edu/people/meaghan-wetherell
wiki/Merycoidodontoidea