All the 2wd trucks in 98 and 99 ran H190s and C200s, are the narrower track axle, and did not have the axle ratios to match what the Xterra have. 1999 4wd V6 trucks have the right H233b, but you would have to weld on new spring perches to do the spring-under mount. The 2wd Desert Runner and Crew Cabs debuted for the 2000 model year and have the axle you'd be searching for, although that was the year the spline count changed and not all of them will have 31 spine axles.