Having had this issue for about a year with my 2015 xp1000, I recently purchased a billet differential with all the bells and whistles. After installing the new differential, SAME ISSUE! Well the only part that was re used from my stock diff was the torsion spring and holder. After speaking with Brandon at HD extreme off road he told me that the spring needed to be tightened. Well having already purchased a new spring and carrier I decided to do some testing. With the old spring in place I measured the force required to overcome the spring and activate the locking mechanism. Force was measured with a spring scale and required 16ft/lbs of force. I installed the new spring and took another measurement. With the new spring it required 21 ft/lbs to overcome the spring pressure. Brandon explained that they have experienced this issue and to correct it they would stretch the spring until it had an at rest measurement of 7/16 of an inch from inside elbow (the bends that wrap around the pin) to inside elbow. I will be reinstalling my diff and testing in the next 2 weeks. I will report the results. One last observation. A visual inspection of the old spring and new spring showed an obvious difference as the old spring had obviously collapsed some and my testing showed it had lost appx 25% of its tension which we all know holds the sprag carrier in the neutral position until the 4wd switch is activated.

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