2006 Tundra 4WD - Front Diff, Amsoil SVG 75W-90

[btanchors]

Take a look at this interesting UOA for the Front Differential in my 2006 Toyota Tundra Limited Double-Cab 4WD. This gear lube was the second fill (Including the factory fill) for this component. What's particularly interesting is the high TAN. I have had several UOAs on both Amsoil SVG, and Mobil 1 Gear Lubes with high TANS on two different vehicles, using two different labs. I intend to open a separate topic about this in the ATF, Differential, Trans, Brake, and P/S forum shortly. Note this lube was in service for just over 10,000 miles. I did do some light towing on fairly level terrain (MAX 2500 pounds, vehicle rated for 6600). Towing occurred less than 10% of the time. Meanwhile, here is the UOA:

 

[bruce381]

limited slip additive may raise TAN have it checked also
bruce

 

[btanchors]

Bruce -

The Limited Slip additive was present only in the Rear Diff fill on the Tundra. I did not use it in the transfer case or front diff on the Tundra, nor did I use it in the rear diff on the Lexus, since the Lexus has a standard (Not Limited Slip) differential.

 

[bruce381]

in a gear axle i always worry more if the magentic plug picks up "gritty/Flakey" fe that is a sign of bad on the way.

"fuzz" on a drian plug is normal and not a problem if all you have is 100 ppm i do not think you are introuble alwyas there you are just looking for it now.

Al I said web search analysts Inc oakland Ca call Bobby next week tell him bruce sent you and ask about condeming limits and what he tests for in his "gear oil package" he does engine, hydro, trans etc.
bruce

 

[unDummy]

Front axle has smaller sump the rearend. So wear concentration reads higher. Whats the capacity here? xcase? rear?

Si seems high. I know from personal experience that when filling from under, dirt sometimes falls in(threads/dust/funnel/bottle tip). Your next UOA will shed some light here.

I'm not sure of the '06 4wd, but even if power is not sent to front end, its still spinning. This is why some swith to manual hubs(take the load/wear of the frontend when in 2wd).

Flashpoint/visc look perfect. Tan seems to be high but consistent so don't worry about it. You'll want to track your UOAs. Feel free to email your UOA links to Amsoil for their comments.

I would also run the current fill a little longer(15k+). A little more usage on the fluid will help settle numbers some. Consier this battery of Tundra UOAs as a 'breakin' rinse.

Magnet inspection is important. How did they look at 5k and 15k?