Yes there is
zstroken, The drive shaft comes out of the transfer case on all 4WDs right? The sensor measures drive shaft revolutions to determine vehicle speed. IE the transmission is between the engine and the transfer case right? On my 97 there is a speed sensor in the transfer case output that feeds the speedometer. This changes in 98 to only have one speed sensor in the differential housing that feeds both the ABS and the speedometer. I have the heavy duty transfer case in my 97 but it could have come with the light duty one. The heavy duty one was used on all 3500's in 97 but was optional on the 2500's due to having problems with the 3. 54 ratio and the dual wheels which could snap the shaft off in the transfer case if the rear wheels were to hook up on something solid and suddenly apply full load to the transfer case when the mighty torque of a Cummins comes to bear. Hence the 3500s used a larger main shaft/bearing assembly to prevent this. Let me know if you need any more help. Ken Irwin