2013 GMC 1500 SLT 325,000 kms plus 3% for 275/70R18 tires.
F&R Diff; out 75w90 Pet Can in @ 103K kms Sept 2017 In; 80W140 Pet-Can
T-Case, out; PC Dura-Drive ATF, in @ 134K Aug 2018
In Shell THF Spirax, meets JD J20C.
We'll see how THF works in T-cases.
Yep, and the primary function of engine oil is to make money for the blender and downstream marketing.
Manufacture the product as cheaply as possible and sell it for as much money as possible through hype and advertising.
Lie if you have to.
2011 GMC LML Duramax 228,600 kms
out 5W40 Duron Fram ultra
in 10w40 Duron & Hastings filter
2013 GMC 1500 5.3L 234,000 kms
out 5w40 Walmart Euro & Fram ultra
In Duron 10w40 & Castrol branded filter #CAS 10576
Both vehicles had 9% OLM remaining.
Engine oils are always thicker at 100C, or any other temperature than required to prevent the engine from squeaking to a stop if the oil was thinner than required.
That's why I avoid thinner than XW30s and suffer the 1% potential loss in fuel economy.
I'll read where taxi and trucking companies saved $X in extended oil change intervals and/or fuel economy savings.
OK, show me the money.
I didn't think so.
I believe that engine oils are blended to a performance level cheaply as possible, then marketed and hyped as budgets allow.
Most do it yourselfers, (we're talking engine oil here), buy an oil that meets manufactures' warranty requirement, and usually the one on sale.
That puts me in the "oil is...