Motul Gear 300 75W90 reardiff 07 Pathfinder UOA

[Dale_Knight]

Here's a Motul Gear 300 75W-90 UOA analysis report from a 2007 Nissan Pathfinder rear differential (in Nissan Speak: 'rear final drive') with 29,500 kms on the current fill. Truck use is light duty no towing or roof rack use and driven normally at mainly city stop and go and freeway with about 8000 kms on this oil on ice and snow using 4x4. The front diff factory fill was dropped at about 4000 kms and replaced with the Motul Gear 300 '100% synthetic ester based' 75W-90 for general use, truck total mileage is 33,500 kms.

Problem though is the engineer doing the analysis doesn't like the silicon levels in the fluid and flagged it, but as a differential is a fairly closed system and the differential air breathing hose has a small filter on it, I'm wondering if the silicon levels may be coming from seals rather than dirt. Any comments appreciated.

Here's a VOA of the same Motul Gear 300 75W-90 currently in the truck;

 

[INDYMAC]

This UOA looks outstanding. Your guess is as good as mine about where the extra 16PPM of Si came from. I wish this lab would do a viscosity test 100cST. Any idea why they don't?

 

[Dale_Knight]

Originally Posted By: INDYMAC
Your guess is as good as mine about where the extra 16PPM of Si came from.


I'll get under the truck today and see what sort of filter is on the Nissan differential breather hose.

Originally Posted By: INDYMAC
I wish this lab would do a viscosity test 100cST. Any idea why they don't?


Just a matter of asking I think, Ramatek keeps samples on file for several weeks in case a client has a question so I'll ask him to do that test next week. I also noticed that the Tranfer case below was reported as a gear oil rather than an ATF so will get a new analysis of that.