Here is the info you need to properly break in a new t-case or a used unit with new gearing. 

These steps are necessary to prevent damage to your new transfer case components.

Bearings and gear sets must be properly broken in! Improper break-in procedures may cause overloading and overheating of the gears, bearings, as well as a breakdown of the gear oil. Failure to follow the break-in procedure can be identified during inspection and may void the manufacturer’s warranty. Don’t plan on heading up over that mountain pass or hooking up that heavy trailer just yet…. Following the simple guidelines outlined below before you head out will help prevent potential noise issues, damage to gears, bearings, and premature failure.

• Start with 15-20 miles of normal driving at less than highway speeds. Follow this by a STOPPING and allowing the T-case to cool off completely. Repeat this process several times. Avoid any heavy acceleration or high speeds during this break-in step.

• Driving at speeds below 60 mph and driving conservatively for the first 100 miles is highly recommended.

• Drive at least 500 miles and then change out the gear oil before any heavy use or towing.

• It is advised to check and change the gear oil at 2500 miles to flush out any remaining break in debris.

These steps are necessary to prevent damage to your new transfer case components.

FAILURE TO FOLLOW THE ABOVE BREAK-IN PROCEDURE CAN BE IDENTIFIED THROUGH INSPECTION AND MAY VOID THE MANUFACTURER’S WARRANTY