would using 5w20 rp in a 2005 v10 superduty help fuel mileage. some claims are of increases fuel mileage and power definitely needs help with the few mileage 10mpg to date average best 10.6 interstate. if any one has tried it please give your thoughts. currently using motorcraft 5w20 1850 miles to date

 

Yes RP or any other fully synthetic lube can impact efficiency.

Royal Purple and some of the others tend to over hype the benefits and seriously down play the costs. But yes synth is good for a slight increase in mpg over the long run. Unfortunately your truck already uses a pretty darned good semi synth and Ford uses the 5W20 for it's good fuel efficiency already. Hard to improve on already very good.

Now for the bad news you have to change all the rotating assemblies to the synthetics to get any measurable improvement.

Engine, trans, transfer case, and both differentials.

That gets pretty danged expensive in a hurry. Then go to extended change intervals you might break even out 30-40 thousand miles.

But extended change intervals put your new truck warranty at risk... No I am not saying that the lube will cause any damage. But if you do have any damage or breakage, then when Ford researches your maintenance schedule, they have the discretion to deny a claim if you are NOT following their recommended service schedules.

RUBICON

Brother I keep telling you 1800 miles is still brand spanking new and very tight...give that truck and motor some time.

BTW I personally do not recommend changing to full synthetic until a motor is completely broken in... others disagree and jump right to the Mobile 1 at first oil change. ...Your Mileage May Vary! Pun intended

 

What fluid is used in the Torqshift?

The axles already come with synthetic fluid.
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I will bet my 99 Dodge Grand Caravan (with a defunct transmission) that there will be NO gain using RP of the same weight. Save your dough.

*Oh if you win...you have to pick up the van yourself. It may, however, be at the bottom of the Pacific. I have some shark repellant... oh wait...it's a Dodge mini-van. Even a shark wouldn't go near one of those!

 

Mercon II???

 

I use Royal Purple in my '01, don't notice any increase in mileage or power, but what I do notice is that I don't have to add any additional oil between changes like I did when I was using Motorcraft 5W20. Back when I was using the Motorcraft I was changing oil every 3,000 miles and found myself adding a half to one full quart between changes. Since I've switched to the Royal Purple, I have stretched my changes to between 4,000 and 4,500 miles and haven't had to add one drop between changes. I'll continue to use it just for that reason!

 

I agree with others, that the sync RP will help. However, with only 1850 miles on your V10...dude that engine is still tight and needs to be broken in. After 5-10,000 miles and your truck still is having poor mileage, then I would recommend a change. Until then...just use the FORD oil and buy stock in CHEVRON OIL... (just kidding)


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