I f you have the stock locker it is a Gov Lock.
Used by General Motors in 73 & newer trucks that came with an option locking / limited slip differential. It was used in 7.5", 7.625", 8.5", 8.6", 8.875" 12 bolt truck, 9.5", 10.5", and now in the new 11.5" differentials. The smaller designs are fairly weak and the 8.5" and 12 bolt truck designs are especially weak. The 9.5" and 10.5" 14T units are fairly strong and will hold up well to towing and moderate abuse. The Gov-Lock is designed to act as an open differential during normal driving with no force being applied to clutches. This fact that no force is applied to the clutches keeps the clutches from chattering during normal every day driving. When either wheel slips and spins approximately 100 rpm faster than the other a governor assembly senses the difference in speed and activates a ramp system. The ramp system causes the clutches to engage and transfer power to the wheel with traction. One other feature of the Gov-Lock is that it will not engage at vehicle speed above 30 mph. This no lock-up feature keeps the vehicle more stable at higher speeds where both wheels spinning could cause an inexperienced driver to spin out or slide off of the road. This is a great design in theory and works as designed in a stock vehicle that is not abused. The problem is that most of us modify our trucks and many of us abuse them. When this unit is asked to deliver under extreme conditions it tends to self-destruct. The force generated by the ramp system that is used to lock-up the clutches works well, except that same force has to be contained by the case and the case is not always up to the job.
It does not need friction modifier
Gov Locks. AKA. Gov-Bombs
