Join Date: Aug 2002
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Semi O/T: Synthetic Lubricants
friend of mine has a question about synthetic lubricants and it's effect on gas mileage. even though he has dodge durango, i think that basic question about synthetics still applies to any vehicle. He writes:
Subject vehicle - 1998 Dodge Durango 4x4 (part-time) 5.2 liter V8 AT a.k.a. The Gas Hog
I'm going to have virtually ALL lubricants changed. So, we're talking both diffs, transfer case, transmission and engine. For the purposes of my question, let's leave out the front diff and transfer case, since I've engaged 4WD only 3 times in 5 years. In 2WD, the transfer case and
front drive train are dis-engaged.
Question: Will synthetic lubricants in the rear diff and AT result in better gas mileage?
Reason for asking: The shop is telling me that synthetic lubes will not improve gas mileage. I'm having a hard time with that. Lower friction means better gas mileage, right? Or is it not all that great a difference?
Our around town average is 13 MPG, and on the highway we're lucky to see anything better than 15. And the fact that
we drive on the highway at 75 MPH with the AC on doesn't help. But we're driving about 10K miles a year, so that translates to 769 gallons at $2.05 a gallon (current approximate price for mid-grade Chevron). Translating
further, that's $1,576 a year on gas. A 0.5 MPH improvement would save me $57 per year on gas. So it seems to me if I could upgrade to synthetic diff and trans lube for less than an extra $57, then I'd be money ahead.
Not to mention that my wife would not complain *quite as much* about filling the tank on this tank.
So what do you think? Anyway, if anyone has direct experience with measuring gas mileage after switching driveline lubes, please share.