Mutations in CHD8 are among the most common autism-causing genetic defects identified in human genomics studies. Therefore, many labs have attempted to model this disorder by generating mice with mutations in Chd8. Using a gene trap inserted after Exon 31, we created a novel Chd8 mutant mouse (Chd8 +/E31T) and characterized its behavior on several different assays thought to have face validity for the human condition, attempting to model both the core symptoms (repetitive behaviors and social communication impairments) and common comorbidities (motor deficits, anxiety, and intellectual disability). We found that Chd8 +/E31T mice showed no difference compared to wild-type mice in amount of self-grooming, reproducing the negative finding most other studies have reported. Unlike some of the other published lines, Chd8 +/E31T mice did not show deficits in the three-chamber test for social novelty preference. A few studies have examined ultrasonic vocalizations in Chd8 mutant mice, but we are the first to report an increase in call length for adult mice. Additionally, we found that in contrast to previous published lines, Chd8 +/E31T mice displayed no anxiety-like behaviors or learning impairments but showed paradoxically significant improvement in motor function. The inconsistencies in behavioral phenotypes in the Chd8 mutant mice generated by different laboratories poses a challenge for modeling autism spectrum disorder and preclinical studies in mice going forward and warrants further investigation into the molecular consequences of the different mutations in Chd8 and the functional impact on behavior.