It's official... Picked me up about 3 MPG this week...
 

So this last week, I changed almost every single fluid on the vehicle... Except for coolant which was done when I got the Durango. I have been getting roughly 11-12 MPG the past 9 months of owning it. While I understood that it was an SUV, heavy, bla bla bla, I still felt this was a bit low, it doesn't matter how I drove the car, constant 11-12 MPG... This was via the overhead info panel AND manual calculations done while at the pump... The difference was always less than .5MPG between manual and overhead info...

Everything was good sensor wise, tire pressures were good and I just couldn't understand why I could NEVER achieve the mileage ratings that others have gotten... So, here is what I did to improve from 11-12 MPG to 14-15 MPG.

Front and rear differential fluids - 75W-30 Royal Purple - Old fluid in the rear diff was VERY thin and VERY white... It flowed like water... The front diff was the exact opposite... Black and VERY thick... Both fluids had almost no smell to them to indicate it was gear oil... Thought this was very odd...

Transfer case fluid - ATF +4 Castrol - while this, I am sure, didn't help improve my mileage, I would like to add that before changing this fluid, it would take a good 1/2 mile for 4 wheel drive to engage and it was hard to move the lever... After the change, it engaged almost immediately and was very smooth to initiate... Old fluid was also black.

I think what made the biggest change was the oil change... I usually use and swear by Mobile 1 with OEM filters... OEM filters will NEVER change in my book, but when I was shopping for oil, I went to three stores, all of which were OUT OF MOBILE 1! What to do? I was tired of looking for it so decided to see what Autozone had that I could use... One thing that caught my attention was the Q Torque 10W-30 full synthetic made for 4x4's and trucks... WHY NOT!?

I grabbed 5 quarts and went home and changed the oil... When I opened the first bottle to coat the filter o-ring, I noticed that the oil felt very soft and rubbed VERY smooth between the fingers... I have never felt an oil like this before! It seems to flow fairly nice out of the bottle too! I think I may have just found a new oil! But wait!

After getting everything done and topping off the 4.5 quarts, I start the Durango up... For a good 2 minutes I had this slightly loud lifter tick that I have never heard before! Okay, time to drive the Magnum R/T somewhere else and get some Mobile 1... But first I'll take it for my test drive... As soon as revved up a little to get some oil flowing the tick went away... Alright... Hit the road and do a smoothly accelerate to 60 MPH... Holy cow that was very smooth! The engine was also very quiet! Came to a stop, did a WOT run to 60 this time... WOW! I couldn't BELIEVE the improvement in how the motor felt and sounded. I have found my new oil for the Durango, at least for now...

Two tanks later I have found that my mileage went up by roughly 3 MPG!

No real point to this thread and I am sure no one will read it all, but I just wanted to rant and give a possible alternative to those that cannot find their favorite oil in stock, like me...

Hey man I use that Q Torque 10W-30 full synthetic made for 4x4's and trucks too
The Walmarts down here in my area have stopped selling it because of slow sales I
I went to go buy some the other day and lucked up, found three 5 quart bottles for 33 plus tax
Man that's some good stuff!

Did you notice any notable improvements?

Yes, a diff when I stepped on the gas pedal.It would feel like It has more power. I can say gas mileage has been stable @16 hwy/12-13 city.
Not much better or less than fac mileage specs

^ LOL ^

1. You used the wrong gear oil.

2. If fluid cam out white you have water in the diff.

3. You didn't put in enough oil into the motor and wonder why you have a TICK?..........R/T Magnum takes 5.5 quarts.

4. 11-12 MPG's I could have told you theres a problem.

5. Mobil 1 IMHO kicks Q to the curb....... But that's for this thread:
Oil Questions?


But....... All in all a noticable increase can occur but you need to do a tune up as well.

1. I almost doubt that a minor 5W off is going to hurt... Hell, it might even help!

2. That is what I figured with the condition of the old fluid... However, I set it aside after draining and let it sit for two days... NO water, it sort of darkened up... Strange for sure!

3. Owners manual says 4.5 quarts including filter, also oil level was to the top of the "safe" zone on the dipstick... And this is what I mean, by Magnum R/T... THIS Maggy R/T takes 7 quarts....

Attachment 108098

4. I am sure that a problem still exists as doing a simple oil change will not "fix" any problem, but it sure did make the mileage go up!

5. Again, I will not use ANYTHING but M1 in any of my other vehicles, but this stuff being $1-2 cheaper per quart and the results I got, may have given me a new oil for the Durango... This is actually the 2nd time I have strayed from M1, the other time was with Royal Purple in my Audi's... Didn't like it so I came back to M1... Again, we will see at the end of this change...

And I had a tune up done with genuine Mopar parts 10k miles ago... I am 95% sure that my problem with my gas mileage and lack of power, lies with the tranny... I don't think it has even been cracked open as the paint is still lined up on the tranny pan bolts... So, my next step is going to be just that... Also going to adjust the bands while I am in there....

With this being my 1st automatic vehicle ever, I know that you usually only need a small amount of fluid from what the manual calls for... So if I get the filter and gasket for the tranny, how much fluid am I going to need.... Is there any way to help get the most fluids out as possible? I might just take it to my old shop where I used to work and have them do the complete tranny service... They'd probably let me do it myself, but I was the glass/muffler/electronics guy! LOL!

OEM is 80W-90 so you are way off then just 5. And second did ya need the friction modifier?

Also, depending on the motor is your expected fuel milage. Since you said that the owners manual say's 4.5 quarts then you must have a 4.7L so enjoy setting the band adjustment on that one.......

Hint......There isn't one........You will need about 4-5 quarts ATF+4 (Type 9602) for the 42RE.

Uh, my bad... 75w-90! LOL! No friction mod needed since I have no posi...

As per my 1999 owners manual, page 181, the 5.2L takes 4.5 quarts... The manual says WITHOUT FILTER but mine will only take 4.5 WITH FILTER.... Yes, I fill up the oil, let the car run for 2 minutes, rev it a bit, shut the vehicle off for 10 minutes and add 1/2 quart and all is good...

idk where you hear the 4.7 only takes 4.5 quarts of oil, but mine takes 6, and my dads 3.9 only takes 4 :eek: idk why there is such a difference but im pretty sure all the engines listed in my dads manual from that series of engines (3.9/5.9)(not real sure on that) so i DO believe that the 5.2 takes 4.5 quarts with filter, if anyone has any ideas on why the 4.7 takes so much more oil than the other engines let me know

I swear by Castrol Syntec. This is all I ever used in all my dodge vehicles and never had engine trouble yet. But that is my personal recommendation. My 07 Jetta uses only mobile 1 only because it is the only maker to make such a odd weight. I think it was 5w/50 or something like that.

All in all, My D is running super smooth and its been mechanically taken care of since I owned it at 21k. It used to get around 11-12 city driving, but lately my MPG is sumped down to 9-10 mpg city regardless of its mint running condition and its severe maintenance schedule I put on it. I am pretty sure my 02 sensors are going out causing this bad MPG as my truck is approaching 90k miles. No codes on anything, but I am betting my 02 sensors are worn enough to kill my MPG's. Gonna replace all the O2 sensors when my uncle sam paycheck arrives. Cannot drive my truck much anymore with this crappy MPG and fuel prices are on the rise again.

WELCOME BACK!!

Kensai, welcome back!! we saw you were off the frequency for a bit, I thought that maybe HYDRA put you on probation!! (LOL!!) Just because you werent driving, doesn't mean you can't post!!

I was reading about O2 sensors going, and causing decreased fuel mileage even though the codes aren't there. It sounds a good time to change mine, I am at 101K at least the before cat ones. If I replace it will it throw a code until the new one gets "Broken in" or should it just be plug and play?

Wonder if the bad fuel mileage is due to your IR plugs?........

^ LOL ^

No doubt Tommy!

Plug and play but you need to reset the computer so you won't get good gas mileage for the first little as seen here: Engine Code Index (Check Engine Light?)

HYDRA,

NO IR HERE. I tried the Autolite Platinum for a short time, but they werent long. I have been on Autolite Copper since Indy D and I believe you set me straight. I am thinking of changing the before CAT O2 sensors but the ones I see at least at A/Z are the ones you have to assemble the wiring, any ideas on where I can find one that is really plug and play with the connector already assembled.?

I am still here, just not checking in as often as I would like. I am pretty much in the same boat as Mean green as far as going back to school. It's about time I finish what I started and that is to get me a 4 year engineering degree. UNT Denton has a new one of a kind engineering field that deals with energy conservation. Since I had once been a HVAC A/C guy for quite a few years, I understand the energy concept.

So having a full time Information Tech job and a full family to take care of, the most spare time I can muster is just part time school. Taking just 2 classes per semester. Lucikly Uncle SAM has the lifetime learning and hope tax credit that I can fully deduct my education! Free education is better than no education! :)

Otherwise, I do respond to any messages I can relate to and can firmly give a sound answer to.

Nope, my IR plugs gave me same or slightly better mileage. I must assume (I hate assuming things) that it is because my Truck has been garage for so long, the sensors and all the other stuff may tend to gum up a little from idling fluids and what not. These IR plugs are still Champion Truck plugs as well. Took a few of them off for inspection and they are still super clean.

Keeping up with a routine full severe maintenance schedule on my D, the only thing left to check is my 02 sensors. I have replaced just about all the other sensors knowned to go out on a 1st gen durango in the 90k miles this thing had.

I do agree however, that for some funny reason, once I have changed out my fluids on my diff and tranny, and transfer case all at the same time, the first couple tanks, my MPG's improved by more than 10-15 percent. I usually avg 11-12, but during the first few hundred miles after changing out all the tranny/diff fluids, I noticed the MPG was at 12-13. Then eventually dropped back to 11-12. At first, I thought it was just coincidence. But after replacing my fluids 2 more times in the life of my Durango, both times, it temporary showed a MPG improvement.

So definitely something in the tranny, transfer case, and differentials made a temporary MPG improvement when running new fluids thru them. I just wished the improvement would last much much longer!

The only thing I could suggest is only use Fully Synthetic Fluids. They break down slower than regular lubricants. Also with the PCM learning the truck could change things back to normal.

Dang PCM... It can't be fooled like my wife:cool:

I like the OEM ones.

Hydra, you know me, I only use the highest grade materials available for my D. So if I use full synthetic Castrol Oil, you betcha I do the same for all other fluids. I am using ATF+4 so that is 100 percent synthetic, but not sure about the gear oil.

Also would not know how or why the PCM would relearn things just by changing fluids on the tranny and axles unless there are sensors that say "lookie lookie, new clean fluids"

I guess the PCM Just can't be fooled to think other than stock.

OEM really put intelex into those things, but they can be fooled somewhat.

Of course I know what you run.....LOL.....Just put that up there for others. :D


Just a hunch on the PCM learning because it always happens.... :rolleyes: