you have to take the a/c comp off, lower rad. hose., alternator, and cab heater/trans cooler lines. Its held on be 3 15mm bolts and 3 13mm bolts. There is a square cut o-ring behind it that you will probably have to get from cummins. There is a few hoses that might be leaking in that area. I would make sure everything is tight and pressure test it if you can. It might also be that the water weep hole is leaking and running off the gear housing. Good luck