- Joined
- Sep 26, 2010
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- 9,807
Here is the second UOA on the rear axle. The cumulative iron is 900PPM which continues to set a record from my experience performing UOAs on various axles with varying mileage and use cases. The iron did reduce by slightly less than 50% from the first UOA, which is good and is as it should be, though I would have expected it to reduce a bit further--especially since I upped the viscosity from 80W-90 to 75W-140. I have to say that FCA screwed the pooch on the factory fill since they recommend 75W-140 for towing and my Rubicon has a towing package, yet they filled it with 80W-90.
Otherwise, all other elements reduced in count. However, there was some shearing that happened as the viscosity reduced from 26.4 for virgin oil to 22.8 and the TAN (acid) levels were slightly higher at 2.43 versus 3.10 for virgin oil--though this is not cause for concern as most gear oils are acidic in nature.
I topped the level off after pulling the sample and I will likely take 2 more samples (one at 15K and one at 20K) before calling it good. Depending on what I see in the 15K and 20K samples, I will determine the OCI for the rear axle and settle into that regime. At 1.6QTs capacity, it is not like I am going to break the bank even if I settle into a shorter OCI than I have with previous vehicles.
From a cursory point of view (since I have limited data), these axles **appear** to be harder on oil than larger axles such as Sterling 8.8", Sterling 9.75", Sterling 10.5", and Dana 60 axles. In my experience, none of the aforementioned axles have produced the wear metals nor the shearing that I have seen with this Dana 44. Time will tell if that means anything.
At any rate, enjoy!
Otherwise, all other elements reduced in count. However, there was some shearing that happened as the viscosity reduced from 26.4 for virgin oil to 22.8 and the TAN (acid) levels were slightly higher at 2.43 versus 3.10 for virgin oil--though this is not cause for concern as most gear oils are acidic in nature.
I topped the level off after pulling the sample and I will likely take 2 more samples (one at 15K and one at 20K) before calling it good. Depending on what I see in the 15K and 20K samples, I will determine the OCI for the rear axle and settle into that regime. At 1.6QTs capacity, it is not like I am going to break the bank even if I settle into a shorter OCI than I have with previous vehicles.
From a cursory point of view (since I have limited data), these axles **appear** to be harder on oil than larger axles such as Sterling 8.8", Sterling 9.75", Sterling 10.5", and Dana 60 axles. In my experience, none of the aforementioned axles have produced the wear metals nor the shearing that I have seen with this Dana 44. Time will tell if that means anything.
At any rate, enjoy!