I will be watching this thread, as I have a 450 with 4.88's and mileage is still on the low side.
I would like the same mileage I get doing 60 at 75, which the gear vendor would do it.
I think it would be the best for you guys with the 4.88's and factory tires . Should really reduce the rpm's when cruising and have the ratio needed to get the big loads rolling from a start.
Are the trucks stock? With a modded truck re gearing and still getting the load rolling shouldn't be a problem, these trucks can make a boat load of power. Seriously tho.. If you can throw a bigger tire on it, it'll bring the ratio down some.
It's still stock. It does not lack power. At 70 it's doing 2450 and 9 mpg. Oh yeah don't want bigger
Tires because speedo has to stay accurate. When we tote the bote the trailer is too wide to run without a dot number and a lot of paperwork to be oversize. Not to mention laying out every route. So getting stopped for speeding is not an option lol.
a friend of mine went through 4 of those units. 4.88 gears and a lot of weight. truck weighs 11.000,the trailer and load weighs16.500. those gv units dont play well with alot of weight. he removed it.
If your going to mod it I would gear down. These trucks have tons of power to get anything rolling.. Erikclaw has a similar thread going about gearing down also.
How big do you tow?
Our 350 dually with 4.10's stock moves our 16K equipment trailer no problem but I do feel it falls on it's face a bit at the upper speeds. This is mostly because i'm use to my extreme street tuned truck I think. I have pulled it with the 150 tune before tho and it was great. I bet someone could make you a pretty badass tow tune depending on how heavy your total weight is. The tune size will also depend on how much you wanna mod.. the more you do to keep temps down the more fuel/power you can tow with.
That's about what our 36ft Eliminator Daytona Weighs, maybe a bit more, considering its got a super built Extreme Triple Dually Trailer on it, the F350 Dually does just fine!
You can tow with the GV. I have alot of miles on mine towing and unloaded. Check the facts at GV website. 30,000 GCVW. If you haul constant and commercal they only recommed 25,000 GCVW and a HD cooler. Its lower just to extend the life of the unit it reads. I average 30,000 lbs when I tow. I would only recommend towing with the 4.88 on a stock motor. You will need more power to tow with the 4.30. The only thing is you have to disengage the unit when your going down hill using engine retarding. It will burn the clutch in it. It also takes some learning to shift it with a auto. We have two trucks with them and they have been great.
FYI:I would also add the new 2011 6 speed autos are double od already. So no need for it in your next truck.
I have an 08 F450 with 4.88 gears before I would only get 9MPG I tuned and deleted and now I get 17.5 to 20MPG "empty" depending on how I drive it. Running 70MPH I am usually around 2400 to 2600 RPM's I would like to drop my gearing also I think that would help out with MPG's But I am holding off cause I have a set of American Force 22.5's in my line of sight and after they are on the truck wait and see how I am looking RPM wise
LOL It has to be the lie o meter. I can only get 15 -16 at that speed w/ the gear vender and 4.30 gears. The truck weighs 10,000 empty for goodness sake.
You have to be in the flats to get that. There better not be a hill in site! Not to mention you have to do a whole tank non stop. My super meter reads 24mpg. LOL
I have an 08 with 4.88's and a spartan set on 250 all the time. Yesterday I was hauling a 16,000-17,000 lbs tractor through some nice rolling hills. I was doing 65 mph the entire time and was able to hold and even accelerate to pass on the inclines. Mind you the clutch would slip when accelerating. I didn't calculate milage but even at 8 mpg, it outperforms any other truck in those conditions
If 4.88s are too low for fuel mileage i would drop to 4.30s.. It wont help a whole whole lot but it will a little.. Hard to expect 15mpg out of a #10k truck turning upwards of 2k rpm nearly all the time
The 4.88 with the gv at 75 is 2150 or 2200. Its a 500 rpm drop. Its hard to beat on the empty side and still have the gears to pull the hills when you dont need it. The 4.30 is another 150 below that if I remember right. I have two friends now that just bought new trucks and want to sell there units. one is sold to a guy here and the other one just came up. Same price. Again you cant really tow stock with 4.30s and the gv. 4.88 is the key for stock trucks.
We have installed alot of gearvendors on trucks with great success. Knocks 500 rpm out of em like heavy haul stated. I just did an 08 F550 with a gear vendors and a dpf delete with Kem tuning. Haven't heard from him on what mpg increases yet, but he is very happy with how the truck runs and pulls his fifth wheel now.
I have a gear vendor for sale with low miles on it that came off of a 5R110 in my 6.0l when I sold it. I will take pics and send them to you.
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