When I'm pulling at 63 mph and getting the above mileage, I have the OD turned off which locks the torque converter in 3rd gear. At that speed my 5.7 HEMI is turning 3000 (4.10s will do that for you) and singing nicely throught the SS Magnaflow. 
Towing Sailfish 272 with a D-max
- Thread starter SBLGFD
- Start date
Interesting what Okletsfish says..If there's a rash of newer models, getting bad mileage that would explain a lot...Our trucks run really well and get, I repeat, 16-18 or so empty.
gw204;
We don't have the "OD-off" feature..We both have the "Tow-Haul" switch. Since there's no option to "lock-out" overdrive, I assume that the "Tow-Haul" mode does the equivalent, whatever that is.
Funny you should mention your gas 2500..I have a '98 Chev 2500 with a 454 that gets 7-8 when I towed my Gulfstream at first, before I got my Dodge.
Kenlahr;
Jason and I both have the 3:73 ratio..Sounds like you do too. The dealer and the techs told me that 4:10 gears would be a waste of fuel for our towing needs. My Dodge, and Jason's Duramax are rated to pull much more than the 10,000 LBS my Gulfstream is.
To the dude who started this thread....My apologies for "expanding" your original topic..Hopefully all this discussion ties into what your doing and gives you more info.
One more Grady-oriented thing..I seem to be a classic example of how weight can add up in a hurry.
I do travel with full-fuel...(I was told to keep the tanks full due to Ethanol,) I have 200 four-strokes and a pretty massive galvanized trailer. Add anchors, bags and all the stuff and I'm heavier than gw204's Sailfish which is 4 feet longer.
gw204;
We don't have the "OD-off" feature..We both have the "Tow-Haul" switch. Since there's no option to "lock-out" overdrive, I assume that the "Tow-Haul" mode does the equivalent, whatever that is.
Funny you should mention your gas 2500..I have a '98 Chev 2500 with a 454 that gets 7-8 when I towed my Gulfstream at first, before I got my Dodge.
Kenlahr;
Jason and I both have the 3:73 ratio..Sounds like you do too. The dealer and the techs told me that 4:10 gears would be a waste of fuel for our towing needs. My Dodge, and Jason's Duramax are rated to pull much more than the 10,000 LBS my Gulfstream is.
To the dude who started this thread....My apologies for "expanding" your original topic..Hopefully all this discussion ties into what your doing and gives you more info.
One more Grady-oriented thing..I seem to be a classic example of how weight can add up in a hurry.
I do travel with full-fuel...(I was told to keep the tanks full due to Ethanol,) I have 200 four-strokes and a pretty massive galvanized trailer. Add anchors, bags and all the stuff and I'm heavier than gw204's Sailfish which is 4 feet longer.
I'm not 100% sure how the Tow/Haul mode works on Dodge, but on my wife's '02 Suburban it actually causes the trans to shift harder and hold gears longer.
My OD off only gives me lockup in third, no change to shift points or firmness. At first I didn't like it, but after I figured out how to work with it, it's pretty cool. From a standing start, I leave the OD on and just push on the pedal a bit more. Once I get to highway speed, I turn the OD off, get immediate lockup and set the cruise. She'll pull all day long and just downshift on the hills.
My OD off only gives me lockup in third, no change to shift points or firmness. At first I didn't like it, but after I figured out how to work with it, it's pretty cool. From a standing start, I leave the OD on and just push on the pedal a bit more. Once I get to highway speed, I turn the OD off, get immediate lockup and set the cruise. She'll pull all day long and just downshift on the hills.
As the guy that started this post - I think this is going in the right direction - lots of good info. As a FYI here is a dreat D-max forum lots of great ideas / tips and help. I am sure many of you have been here but if not its worth loking at it.
Chris
http://www.dieselplace.com/forum/
Chris
http://www.dieselplace.com/forum/
iam pulling 24' offshore full gear 05 Duramax 2500 crew cab 10 -11 mpg running about 68mph plenty of power dont know its back there riding on a loadrite 06 tracks great motor is quiet only problem radio sucks
magicalbill said:
Bill, if you have an Allison trans, pushing in and holding the tow-haul button will light up the OD lockout in the dash. I found mine by accident, then looked it up in the owners manual and sure enough it was there. I have 32" tires so OD doesn't kick in when towing 'till it gets to about 62.
And yes, the tow-haul mode re-maps the trans shift points and fluid pressure. They shift more crisply, hold the gears longer, shift down automatically for slowing, and keep the engine at optimum rpm for power. They work REALLY well for towing and no problem at all with big loads, up to 15K lbs. Just make sure you change out that tow bar, the factory one is good for about 6500lbs.
If any of your '01-'04 d-maxes are getting poor mileage, it's most likely due to failed injectors. 80% of them either have been replaced or will be replaced under an extended warranty campaign thru GM/Bosche.
Mine is an '03 with almost 60K, gets 20-22 empty on the hiway, 13-14 towing the 208 (about 5K lbs) and about 15-17 combined/empty. Injectors were replaced at about 46K. And yes, they all have 3.83 gears.
CJ;
Thanks for the info..Did'nt know that!!
That's why this site is cool..
My truck is the '07 Dodge..My son Jason has the Duramax, circa '06. I will certainly let him know about the OD-lockout feature you described.
I wonder if his injectors are suspect?
Next time I drive my Dodge(I have a Toyota for everyday use,) I'll hold in the Tow-Haul switch..Probably a long shot, but maybe that'll lock out my OD on the Dodge.
Here's another thought. Jason and I have complained far-and-wide about our lousy towing mileage and most of the dudes we talk to say to get a "Cold-Air Return" for the exhaust. Some also say you can get a computer chip to boost efficency also. I have not done either, as I have to look into whether it would affect warranty coverage.
So, the big question...To all who get the decent mileage...Are your rigs stock-factory, or have you done custom work, like the cold-air thing, to improve the mileage?
Our trucks are untouched, but we need to do something.Taking my Gulfstream to Fla at 8-9 MPG paying $3.30-plus is, well...I don't have to tell you...
Thanks for the info..Did'nt know that!!
That's why this site is cool..
My truck is the '07 Dodge..My son Jason has the Duramax, circa '06. I will certainly let him know about the OD-lockout feature you described.
I wonder if his injectors are suspect?
Next time I drive my Dodge(I have a Toyota for everyday use,) I'll hold in the Tow-Haul switch..Probably a long shot, but maybe that'll lock out my OD on the Dodge.
Here's another thought. Jason and I have complained far-and-wide about our lousy towing mileage and most of the dudes we talk to say to get a "Cold-Air Return" for the exhaust. Some also say you can get a computer chip to boost efficency also. I have not done either, as I have to look into whether it would affect warranty coverage.
So, the big question...To all who get the decent mileage...Are your rigs stock-factory, or have you done custom work, like the cold-air thing, to improve the mileage?
Our trucks are untouched, but we need to do something.Taking my Gulfstream to Fla at 8-9 MPG paying $3.30-plus is, well...I don't have to tell you...
06 Duramax/Allison Crew Cab Shortbed 4x4 with the 3:73 rears and two sizes larger than stock Michelin LTX E rated radials inflated to the rated max pressure. Towing our 93 Sailfish with full fuel, gear, 2-4 people in the cab, my all time best is tight at 10-11 mpg @ 65 mph. If I tow at greater speed, mileage goes to the single digits, although I have never hand calc'd it less than 9. We tow from Central Florida to the East Coast (Cape Canaveral) all the time so its a good mixed back of two lane roads, stop and go driving and highway. Headwinds will kill the mileage, especially if you have a hardtop and large radar like we have.
Unloaded mileage I can get around 17-18 in town and 20-21 mpg on the highway at 65-70. 75-80 mph yeilds mileage around 17-19. I agree with the comment about keeping the revs below 2,000. That seems to be the majic number for best mileage.
These newer diesels (Dodge, Ford and GM) have been tweaked for HP and Torque at the expense of mileage. Mine pumps out 360 hp and 660 ft/lbs at 1800rpms. Way more power that what is really needed. IMHO, if you are looking for mileage, look for an older 1st or 2nd gen Cummins 12v as a pull vehicle or consider adding a tuner to your rig. Some say they have seen improvements of a couple MPGs running a mild tune to the diesels.
My experience has been you still get better mileage than a comparable gas powered truck but the advantages to having a diesel have been decreased since the newer trucks aren't as efficient as in previous generations, the govt raising the standards for fuel (ULSD) which costs much more to refine (bunch of BS), and the newer emissions requirements that are incorporated on these motors.
Such is life. Still brings a big smile to my face everytime I turn the key and hear the diesel fire up.
Unloaded mileage I can get around 17-18 in town and 20-21 mpg on the highway at 65-70. 75-80 mph yeilds mileage around 17-19. I agree with the comment about keeping the revs below 2,000. That seems to be the majic number for best mileage.
These newer diesels (Dodge, Ford and GM) have been tweaked for HP and Torque at the expense of mileage. Mine pumps out 360 hp and 660 ft/lbs at 1800rpms. Way more power that what is really needed. IMHO, if you are looking for mileage, look for an older 1st or 2nd gen Cummins 12v as a pull vehicle or consider adding a tuner to your rig. Some say they have seen improvements of a couple MPGs running a mild tune to the diesels.
My experience has been you still get better mileage than a comparable gas powered truck but the advantages to having a diesel have been decreased since the newer trucks aren't as efficient as in previous generations, the govt raising the standards for fuel (ULSD) which costs much more to refine (bunch of BS), and the newer emissions requirements that are incorporated on these motors.
Such is life. Still brings a big smile to my face everytime I turn the key and hear the diesel fire up.
magicalbill said:
Yeah, I don't know about the Dodge, but you should be able to lock out OD, it's pretty standard/common. The '06 d-max has an updated injector and did not have the problem like the LB7 series engine. There is TONS of info on these trucks here: www.dieselplace.com Everything I know came from there... :mrgreen:
The cold-air thingy is a 'cold air intake'. It's a custom intake plenum that isolates the airbox and intake from the heat of the engine compartment. They really doesn't do that much and they are expensive. All of the new rigs have a pretty good intake setup already. In filter flow tests, an AC Delco paper does as good as any of them, and traps more dirt than the foam units. Plus you don't have to worry about fouling your MAF sensor with filter oil if you put too much on that K&N or AFE.
If you chip the motor, do the intake, and the exhaust, you can pump a LOT of power out of them - up to 800hp and 1000ft/lbs of torque. But you can 'limp' your tranny and delight in premature engine failure. There are problems with EGT's and general engine temps too. I would not buy a rig that someone else chipped. A very mild tune, like a 50hp bump may make some sense for towing, any more and you're just asking for a melt-down. My little old LB7 only puts out about 600ft/lbs of torque, guess I'll just have to live with it 8)
Seriously, if you're only getting 8-9 there must be something else going on there. Tunacious is right on the money with numbers and reasons for late model performance declines.
I agree 8-9 seems awful for a diesel. From what I hear that's what the big block gassers get and gas is cheaper. As they made more power, the mileage went down a little with the LBZ and LMM but that's a steep price to pay for that much power.
yes its a boise. dealer replaced it 3 times poor reception very soon ill up grade just got done plowing
Here, check out this site and thread. http://dieselplace.com/forum/showthread.php?t=203547rnorrk said:
Well we bought the boat - haven’t towed it enough to tell what’s what - probably going to replace the new trailer ( Venture) thats under it with something a little heavier - Hi-Tec aluminum or Loadmaster galvanized. But on the mileage issue 18.5-19.0 using GPS over 1200 miles pulling nothing. When I pull her home I will post the loaded mileage.
Chris
Chris
SBLGFD said:
How exciting, I'm jeoulous! I think they are an excellent boat.
18-19 unloaded on your diesel is a little low, but I don't recall your year. If it's one of the new ones that may be about right, they use a little more fuel than the earlier model. Also, if your speed is over 65 that will also do it, they push a lot of air. And hilly terrain will drop your overall.
Pulling 10K lbs at 55 will probably give you 10-12, which is a whole lot better than a big-block gas which get about 7-8. I have the 8.1 in my Winnebago with the Allison 5spd, it's about 18,500lbs and gets 8.5-9 not towing, and 7-7.5 with the a toad or the boat. A 600 mile trip to the river for some water sports is a $350 bill at least :shock: Plus beer!
Keep us posted...
oasis04
Member
Well i must chime in I had an '02 stroke with only a super chip added. I got 17.5 towing a 20' runabout and the largest coleman pop up camper they made. to tal rig was well over 16000 and 67' long. (yes I measured it) limit is 70'. Not only did i get those numbers i was pulling this rig over the Rocky Mtns. from Denver to Lake Powell. Summer time A/C on Overdrive selected the computer knows when to shift. My egt never exceeded 1050 degrees and my trans temp was only slightly warmer than running around light engine. this truck got 21.5 mpg light and had the 3.73 rear end and would pull any thing i hooked to. friends with 4.10 rearends can pull harder but economy goes out the window above about 2200 rpms. Also a Deisel guru I know says make sure you adding lube to your fuel aas the new lowsulfur fuel is hard on the injectors and pumps. I followed this advice on a recent tow of 500 miles and saw a noticeable change.
Sorry for rambling hope this is useful info to some.
Oasis04
Hoping to be a grady owner this yr.
Sorry for rambling hope this is useful info to some.
Oasis04
Hoping to be a grady owner this yr.