johnr9q

I was talking on the phone with Curt from GearVendors (an overdrive unit that can be installed on the Dodge for somewhere around $3500) He told me of a magazine article which stated they got close to 30mpg at 75 mph empty with a gear vendors unit. I have to drive 45 mph to get close to 30 mpg empty. I emailed him back and questioned him and he said maybe the Dodge had other alterations but said the OD unit is probably the bigest factor in improving the MPG. I think he is probably correct on that point. Following is the article: http://dodgetruckworld.tenmagazines....ticle&aid=2798

mikmaze

I would be happy with 25 mpg, if that thing could do it, I should have bought it long ago............ but reality sets in, these trucks are heav, have the drag coeficient of the empire state building, and soonere or later it is going to take fuel to move the truck. rpm means little in the equation, you do not burn a set amount of fuel at a set rpm, it depends on a lot of things.

Danderson

My buddy did the Dynatrac conversion and the Gearvendors OD and picked up 3.5 mpg.

mad1

Thats a lot of money spent for 3.5 mpg. $ 2000 + install for the hubs and $3500 for the OD. My opinion not worth it for close to $6000!

gadget.35-06

You have to factor-in the savings in wear and tear over the long term as well.

mad1

I feel that the hub kit is worth it, I put the EMS kit on mine as well. As far as the OD unit what wear and tear do you save there?

Raspy

This sounds like total sales BS to me. It is the same old tired logic that says, something to the effect that, "a 20% decrease in RPM equals a 20% increase in mileage" Well, it just isn't so. That pesky old wind resistance, and its brother, friction, always come along to mess things up.

30 MPG at 75 MPG. "Yeah, prove it" is the first thing I would say to anyone that tried to sell me something that would do that. Especially a gear box. No way (unless this is down hill or with a big tail wind).

First, the truck produces the same amount of drag at that speed whether it has another OD or not. Every additional gearset adds another approximate 3% increase in frictional losses. The overall resistance of all the mechanical friction and wind resistance is the same. Except, with an additional gearbox the mechanical friction has actually increased. So any overall advantages will only come from reducing some other inefficiency so much that it more than makes up for the friction it adds. The only area that can be improved is the efficiency of the engine and lowering it's RPM from, say 1750 RPM to 1550 RPM, is not going to produce the difference required to add around 8 MPG. Or, in other words, produce more than a 30% increase. Just ain't gonna happen.

Please prove me wrong with actual before and after tests. Please. I'm waiting. Prove me wrong. I'd love to find a 30% increase in mileage at 75 MPH. I'll even participate in the tests and happily shout how wrong I was with my skepticism once proven wrong. Bring on the tests. When do we start? Just take a standard Dodge Cummins with 3.73 gears. Test before and after a Gear Vendors installation with no other modifications and let's see what happens.

Until then, save your money if you're looking for that kind of savings and keep your wary eye handy for those that make the claims.

PS. I already installed the Dynatrac kit. Mainly because it's a better design. But I saw no obvious increase in mileage. Maybe it could have been shown through accurate testing, but not by casual observation. Still, I'm glad I did it, as it's a way better design than the stock unit bearings.

megacabdad

I remember an article in either 4Wheeler Magazine or 4 Wheel and Off - Road we they ran on '03 (I believe, I searched for the link, but couldn't find it) for 20 or 30k miles bone stock, and recorded mileage.

Then, they added a Smarty, CAI, fuel catalyst, GV overdrive, hubs, exhaust, etc...

They did the same exact driving with it, and netted something like a 2.5 mpg increase with all that stuff bolted to it.

You would have to do a lot of driving to pay off the 10 grand they had into to reach any kind of pay back from your investment.

Their final conclusion was that everything they did increased the driving experience of the vehicle.

Did you read this?

Link

Dan Marino

I have said B.S. forever to anyone or any vendor that says they get more than 20 MPG out of their (4wd) 3rd gen. 2wd maybe a different story. I have had 5 of them and none gets better than 18.5-19.5. Its the SO '03 5 speed. Theres no way any 3rd gen is getting in the mid twenties to low 30's per gallon.

Dodgezilla

Dan Dan Dan. That is just not true. At 60 mph my modified 03 truck got 23-24mpg. My current truck really hasn't seen any extended highway miles but the day I got it I got 21mpg driving it home from Front Royal. This is strictly highway miles at 60mph though. As soon as I get off the highway it starts dropping fast. The same happens if I increase the speed. It sucks driving that slow but it IS possible. 30mpg, on the other hand, I just don't know about that....

BossHogg

Ya but its not a great idea to run at too low of RPM on some of these bigger turbos as I recently found out from HTT! I had thrown out some bearings in my turbo from running it at too low of RPM, at least thats what they told me at HTT. The guy at HTT said he normally saw damage from exactly the opposite and that it was wierd, but that I was probably running to low of RPM under acceleration. Like getting onto the highway for example and haveing big tires with 373's.

rip 112

I get 20.2 constantly easy when i don't pull anything for the whole tank. On a good tank I've seen 22.4 (overhead reads 26.7) and with my occasional tows and work, I can usually average 17.8. With the Travel trailer I got 17 flat.

My concern on a GearVendors unit is that it seems like it could end up a weak link, small reservoir of fluid, not rated for extensive towing, and expensive just the same. I believe they can do alot better first. Then maybe I'll buy one. I'd love to roll through the gears and sound like a real rig.

Dan Marino

Well I want one! You would think out of the five I have had Id get one that had in the 20's. Even my 4 friends that have 3rd gens none are getting better than 18-19.

Plus with my Red 03 for every 50 horsepower I added I went down 1 mile per gallon. Im down around 10.5-11 miles per gallon the way its set right now.

Untill I ride with someone that can go 700+ miles on a tank of fuel I will never believe you guys.

molalla1ton

ya, I am a bit sceptical about this but more power to them if that is the case I know I am no were near that mpg but I am hardly stock and not really concerned about it.

Dan Marino

Is that your best friend in the Avatar? I love that picture. He looks like hes a heck of a friend.