98 5.9 Grand Cherokee used the 249 t-case which used a Viscous Coupler type differential in the t-case. Very good AWD t-case IMHO, better at power transfer F/R than the 242. The 249 VC got a bad rap because they tend to start failing about 100k miles and would cause driveline bind as they tend to fail in the locked mode due to contamination of the special fluid inside the coupler.