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Old 12-13-2019, 02:07 AM   #8 (permalink)
JSH
AKA - Jason
 
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Join Date: May 2009
Location: PDX
Posts: 3,600

Adventure Seeker - '04 Chevy Astro - Campervan
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Quote:
Originally Posted by ukiltmybrutha View Post
Does thinner ATF have a measurable effect on fuel economy in an automatic transmission?

Thanks.
In general: Yes. It is amazing how much of our fuel economy targets are hit with new fluids (Engine oil, Transmission oil, Differential oil) It is also maddening for me since I have to install storage and dispensing equipment in a bunch of assembly plants.

In practice: Run the fluid recommended by your manufacturer. It takes us more than a year and millions of miles on dynos, test tracks, and road testing to certify a new oil. There are a bunch of little tweaks that have to be made to use thinner oils. Changes to bearings, seals, oil passages, etc.
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