I believe it was in the long thread "Problem/mileage", but I don't have time to dig through that thread again.

 

Partially true. I have been on this forum for a while and have not seen a post with higher gear ratio than 3.73 on a 6.0. I don't think 235 tires come on these trucks, do they? Seems they are at least 265's.

 

I have been asking about final gearing and last night I went to the dealer and we drove both final ratios. There is a significant difference with the 4:10 and 3:73s about 3-500 RPM in some speed ranges. Since these things have sorry tach markings some interpolation was required. I have talked with most and they recommend less than 2k for milage and at 65-75 the rpms were respectively 2050-2500 (4:10) and 1850-2200 (3:73). The overhead guages were no help since the trucks were not full and probably not reset at all but they did show 8-10Mpg.

BTW the DRW CC did rid better than the SRW SC. I am going to try a SRW CC this weekend to see if I like it.

 

I think you will be sorry if you get 4:10 - my 6.0 with 3:73 has unbelievable pulling power. The five speed (really six) auto with tow-haul mode makes up for the need for lower axle ratios in most cases. We have a new Excursion at work with a 5.4 gas engine with 4:10 and it gets miserable mileage!

 

Ambient temps seem to make a big difference on this truck no matter what fuel is used. Living in Anchorage, Alaska we saw temps in the -20 range and now were in the 80's. Winter-time in town I was getting 6-8mpgs. Now I'm getting 12-14mpgs. Highway I was getting 14-16, now I have seen upwards of 20. That of course represents the difference in winter and summer fuel and the differene in temps. Running summer fuel, I've seen a couple mpgs difference in fuel mileage based on whether ambient is 40-50 degress or 70-90 degrees.

 

That is very large swing, for any motor.

 

I have a new 04 F-250 CC 3.73 gears 6" lift and 315 tires. Just over a thousand miles and I'm getting 11 mpg combo city/hwy. I think the tires are killing my mpg but I don't care, I love the way my truck looks and rides.

 

Hey Gunther did you have your spedometer recalibrated after having the 315's put on. If not that will throw of your spedometer and odometer so you won't get accurate mpg calculations.

 

Motown- I have a Superlift True Speed Calibrator installed and then the truck was checked to be sure it was accurate. And after driving to familiar places the mileage seems to be what it should be.

 

I post my mileage based upon the season. I agree with vellingapa that the season (ambient temps) make a difference. Diesels are very popular in Alaska and everyone that I have talked with has noticed a difference due to the season.

Summer with #2 fuel oil and stock tires; highway 17-20. Best was 21.6 at 70mph. Towing #6000 trailer at 70 over the mountains averages 12-14. Probley would be better if I wasnt passing people as if the trailer wasn't back there. Gotta love the power.

Winter with #1 fuel oil and all four tires studded; highway 15-17. Dont use the travel trailer due to the temperatures. Milleage drops to 13 when it is -40 to -50. Will try some additives this winter to see if they will help increse the millage during the colder months. ( 5 out of 12). Not sure what the studded tires do for millage. Wouldnt change them out if it meant gaining my summer milleage back, to much darn ice.

With that given the worst is still better than I ever got with my 2000 V10. Plus the $.40- $.50 difference in gas and diesel. Diesel being the cheaper. But millage was really never to much of an issue. I love the power and the towing capibilities. For those long trips to Anchorage without bring anything back I just use my wifes Sub. 35-40 a gallon. Funny to listen to her complain about filling her tank up, 14 gallons. Loaned her my truck for a week while I was attending training in Anchorage. I thought she was going to freak out when she had to fill up my truck (40 gallons @ $2.10 gallon). Got to admit that 17-20 seem really good for C/C longbed. These are not light duty trucks.

 

mlb4966

What is the setup on your CC/Longbed? Tranny and gear ratio? What is your build date? I'm researching the mileage issue for possible purchase of a new F350 CC LB 4x4 DRW w/Torqueshift and 3.73 gears.

 

I get an average of 17 mpg driving 85 to keep up with Teaxs hwy traffic. That is with a Predator on 65 HP Mode

 

I'm with you. My 3.73s with stock 30.5 tires seems a tad too low for the final OD ratio. I'm at 2300 at 80 with lots of punch. I think it could do with 3.55 s or so for hwy mileage. First gear is really low for about any situation.

 

Well finally got mine on the road today and made a little trip to Biloxi and back 369 miles running 70 mph slightly over 2000 rpm and took 20.001 gals so the way I figure that is right at 18.5 mpg which impresses me. 04 F250 c/c 3.73 with 828 miles after the trip. Haven't been able to find a build date on the engine but the truck build date is 2/15/04. Now to get some more miles and then hook the camper on. If any one has a way to find the build date on the engine besides the valve cover sticker would like to know. Thanks Wes

 

That is OK in my book