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Frequently Asked Questions: Eaton Posi

Find answers to common questions about the Eaton Posi differential here. 

What kind of oil should I use in my Posi? Can I use synthetic oil? Do I need friction additive/modifier?

Eaton Posi differentials perform best when using GL5 rated mineral / petroleum-based gear oil. A four-ounce bottle of friction additive / modifier is also necessary for optimum performance. See the “Lubrication” section of the product manual for further details and specifications. 

Is the Eaton Posi rebuildable?

Yes, there are three main types of service kits available to rebuild your Posi differential: internal spider and axle gear kits, clutch kits, and preload spring and plate kits. 

What is the warranty on my Eaton Performance differential?

Eaton Performance differentials (including Eaton ELocker, Eaton ELocker4, Eaton Posi, Detroit Truetrac, and Detroit Locker) are warranted for one year against manufacturer defects. The full warranty document can be found here.


Can I upgrade my Eaton Posi?

Yes, both the clutch disks and the preload springs can be altered for extreme off road and drag racing applications.

Eaton Posi units come equipped with 400lbs of preload. They can be increased to 800lbs, or even decreased to 300lbs or 200lbs to tune the handling characteristics of the differential to your vehicle. There are several types of clutch service kits in varying friction material style and number of plates. Reference our application guide, or contact the Eaton Performance customer service hotline for details, part numbers, and availability.