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corjunk
Dodge Dakota
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8/29/2007
08:24:13
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 Subject: gears?
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I have a 2000 durango 4x4,4.7l,45rfe,3.55 gears and 31" tires.I bought a 3500lbs (about 5000lbs fully loaded) travel trailer this year that i tow with my durango.It does ok but the 3.55's gotta go.I'm thinking 3.92's or 4.10's. which would be better for towing but still give me decent milage and drivability when not towing.Thanks.
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clint282cc
Dodge Dakota
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8/29/2007
14:21:24
| RE: gears?
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410s hands down.
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Kowalski
GenIII
8/29/2007
16:04:27
| RE: gears?
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Yup - I saw almost 1 mpg increase going from 3.55 to 4.10; several others have seen similar results - all with the 4.7.
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corjunk
Dodge Dakota
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8/30/2007
01:08:41
| RE: gears?
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what kind of rpm's could i expect in 3rd at 100kph.what about in o/d at 100-110kph withoout towing.What kind of trailers do you guys pull with a dakota?durango.thanks again for any info.
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Bob Lincoln
Dodge Dakota
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8/30/2007
08:43:44
| RE: gears?
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Going from 3.55 to 4.10 will decrease, not increase your mileage, unless you are only talking about DURING towing. Engine revs will be higher and it will use more gas. It might help in towing at lower speeds, since the engine won't be lugging as much.
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clint282cc
Dodge Dakota
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8/30/2007
10:25:40
| RE: gears?
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no it makes the tires easier to turn the tires so it doesnt need as much gas to keep it goinng down the road.
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Kowalski
GenIII
8/30/2007
16:09:01
| RE: gears?
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Bob - that's the conventional wisdom; and what I thought too until I swapped. I'm not talking about during towing - I haven't checked yet to see what difference it makes towing. The 4.7 is a rev happy v8; my best guess would be that it might make power more eficiently at the slightly higher revs. Efficiency of a motor isn't necessarily linear with rpm. If Clint's claim was correct, we'd see this gain for all the motors - but that just isn't so. I've pointed that out when he's posted this before, I guess he doesn't read all follow ups after he posts sometimes. Many have seen lower milage with lower gears for other aplications. It's only with the 4.7 that quite a few of us who've made this swap have noticed the slight gain.
corjunk - I pull a 20' flatbed fifth wheel rated at 7500 lbs; and a 24.5' fifth wheel that weighs at least 5500 lbs loaded. I'll get about 11 mpg towing, with no effort toward conservation. Never paid much attention to revs at a particular speed, but its well within the capabilities of a 4.7.
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clint282cc
Dodge Dakota
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8/30/2007
19:44:52
| RE: gears?
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some vehicles come with the right gears so yeah once you lower them the gas milage may decrease. but i think 410s in a dakota with a v8 will increase milage.
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Kowalski
GenIII
8/31/2007
15:22:58
|  RE: gears?
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Clint - If that v8 is a 4.7 - yes. That belief is based on my personal experience; and the reported experiences of others here.
But many Dakotas came with the 5.2 or 5.9 v8s; and no one has ever reported a gain after going to lower gears with those motors. I know of guys who put lower gears behind those motors, and got worse milage; they are very different motors than the 4.7. Just what is the basis for this unusual belief of yours ?
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Kowalski
GenIII
9/01/2007
09:10:54
|  RE: gears?
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Just something you want to believe, like Santa Claus, or the Easter bunny ?
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clint282cc
Dodge Dakota
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9/01/2007
11:19:59
| RE: gears?
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well most of those motors came with 355 gears. but in the r/ts and QC they had 392s. if you were right that would mean that they would get worse gas milage. but they get the same or better. thats my basis for my belief
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daddio
Dodge Dakota
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9/01/2007
15:15:59
| RE: gears?
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QC's do NOT automatically come w/ 3.92 gears. 5.9 or not.
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Kowalski
GenIII
9/01/2007
16:05:19
|  RE: gears?
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Nor do those vehicles get better milage - that's nothing but B.S.
I challenge you to submit any kind of evidence that they do.
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clint282cc
Dodge Dakota
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9/01/2007
17:36:32
| RE: gears?
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all i said was that they dont get worse.
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Kowalski
GenIII
9/02/2007
08:24:42
| RE: gears?
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No, Clint, you might want to reread the thread - you wrongly claimed "they get the same or better". Once something is written in black and white, its tough to deny it. Maybe you should stop posting this kind of B.S. ? Because we will call you on it. Let's keep the info here factual - it's better for everyone.
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clint282cc
Dodge Dakota
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9/02/2007
12:28:01
| RE: gears?
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ok first off what are you bein a bitch for. second off... your right i did say that, my bad. but it still says that they get the same gas milage. if you want go read the gas milage thread and they will all say close to the same milage 5.9 or 4.7
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Kowalski
GenIII
9/02/2007
12:50:33
| RE: gears?
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Just exposing your baseless B.S., not out to be a bitch. Wouldn't be necessary if you just manned up to your mistake. I know you're young; you could learn when to back off when a guy with more experience points out something you said was wrong - instead of inventing a something to back it up. Lots of people inacurately figure miles per tank; or report optimistic figures in most of those "gas milage" threads I've read, I don't believe there's anything really meaningful there. If we had people with the 5.2 or 5.9 engines posting that they got better milage after they switched to lower gears, I would find that meaningful - but they haven't. It is only for the 4.7 that we find guys reporting that. Understand now ?
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clint282cc
Dodge Dakota
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9/02/2007
22:51:15
| RE: gears?
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i did man up and admit my mistake. sorry i didnt listen to you when you say somthin. i guess you right. you convinced me. you win.
explain to me how a motor is more eficient cause of lower gears? it may be at higher rpms but it takes less work on the motor to stay up there. it doesnt matter if you have a honda civic or a ford powerstroke you will get better gas milage by making it easier for the motor to work. and getting lower gears make it easier for the motor to turn the tires. simple as that. i dont need to base that on anything.
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Shoe
GenIII
9/03/2007
14:52:16
| RE: gears?
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Oh, no you didn't!
Finally... a V8. '01 Dodge Dakota RC, 4.7, 5-speed, 3.92 LSD. = R/T Killer.
well at least a stock one
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Kowalski
GenIII
9/03/2007
15:42:19
| RE: gears?
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Yup, he did. Here we go.
Clint it's not as simple as that. You don't need to base that on anything ? Of course you do; or you will be called for the nonsense you post. Obviously you don't like that; it leads to you calling someone a "bitch". So why pursue what you don't understand like that ? If you truly want to learn more, start asking intelligent questions; instead of posting a bunch of B.S. !
You've got some things backwards here. It does matter if you have a Honda Civic or a Ford Powerstroke (which is a diesel by the way, doesn't get gas milage). Generally, a motor isn't as efficient at higher rpms, there is also higher resistance - higher friction. More heat thermally wasted. But have you ever heard of something called volumetric efficiency ? Have you ever heard of how peformance parts should be chosen to work together - that bigger isn't always better for exhaust or intake design ? How cams are chosen for certain powerbands ? Well all this stuff kind of works together, depending on how things are tuned, so that an engine could be a little more efficient at a slightly higher average powerband. It could be fairly optimized exhaust scaveging working well with an intake tuned to flow with good velocity at just the right valve opening characteristics - that stuff isn't the same for all engines. At a certain rpm, those things could come together to work more efficiently than the extra frictional losses that rpm draws. The 4.7 was designed for higher rpm; and I'll say it again (maybe you'll get it this time) - it is the only mopar v8 where I've seen multiple postings of guys swapping to 4.10 gears, and then getting a little better milage. Been here many years before you were even old enough to drive, and the guys with the other motors aren't saying that. If anyone has any intelligent alternate theories as to why it's only with the 4.7 that we've seen this increase, I'd be interested in hearing them - but I won't be wasting any more bandwith on this nonsense from you, Clint.
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clint282cc
Dodge Dakota
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9/03/2007
16:13:39
| RE: gears?
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then dont waste it. odviously you have to be right and so do i. so drop it. ill let you know what kinda gas milage i get once i get my 410s in my rear end.
by the way im not sayin that the lower you go the better. cause i know if you put some 456s in the rear of a 5.2 you would definatly suffer.
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