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2xDakota
Dodge Dakota
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2/01/2004
13:35:48
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 Subject: Truck gear ratio - going lower for impro
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I am trying to find out if it would really be worth me paying $1400.00 for a new set of gears.
First a little history….My truck is a 2000 dodge dakota 4x4 w/ 4.7L QC 3.55 gears, 32” tires and all heavy duty service and trailer tow package. My boat is a 2003 202 w/ 5.0 carb valvo ~4600#. My truck with those gears is rated at around 4800#. With the optional 3.92 gears it is rated at 5800#.
My truck does ok on flat land but really struggles on hills. I am thinking of putting in after market 4.11 gears because we trailer the boat a lot and I would feel more comfortable with some additional capacity as well as increase performance.
My question is – Will I really see increase performance given the same horsepower (235) and torque (295#) by just adding lower gears? I know it will start out better, but will an additional 500 - 700 rpm at highway speeds really give me better performance. And is it worth $1400.00.
Sorry for the long post.
Thanks Ken
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2xDakota
Dodge Dakota
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2/01/2004
13:38:09
| RE: Truck gear ratio - going lower for impro
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Also, Pulling my boat from a stop, the truck does great, even up some steep ramps, I just need more power in the 60-70 mph range, and I am hopping 450+rpm will be enough, I am going to try and find a graph of the torque for the 4.7L somewhere to see where the max is. I could always go with 4.56, OUCH!! Well, I found the torque numbers 295@3200rmp.
Thanks
Ken
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fst4dr
Dodge Dakota
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2/01/2004
14:25:10
| RE: Truck gear ratio - going lower for impro
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Its not the fact that the engine will be operating at a higher rpm that makes the difference, but the fact that with the higher gear ratio the engine will have a better mechanical advantage to make the same power more effective. Think of riding a bike in different gears. You are always providing the same power, but in the high speed gears its harder to pedal. Hope that makes sense.
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2xDakota
Dodge Dakota
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2/01/2004
14:31:13
| RE: Truck gear ratio - going lower for impro
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Thanks, It does make sense. I just don't know if it will be worth it.
It is great w/o the boat(90% of total driving) quick and does well in light off-road. I just want more respone at highway pulling, to keep it from lugging the motor.
I guess I need to do some serious thinking about cost v. gain. $1400.00 which would be the same for 4.11 or 4.56, is way cheaper then a new truck. Do you think I would gain enough from 20-30lbft of torque at the higher rpm to even tell?
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gen1dak
Dodge Dakota
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2/01/2004
15:20:02
| RE: Truck gear ratio - going lower for impro
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Ummmm, I don't see whether it's automatic or standard, but either way, did you ever consider just dropping back a gear/locking out the overdrive?
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2xDakota
Dodge Dakota
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2/01/2004
15:25:14
| RE: Truck gear ratio - going lower for impro
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It's an auto, And I always pull in 3rd. It won't even stay in OD if I am in the gas very much at all.
I just can't figure out if it's worth the money..
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99DAK
Dodge Dakota
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2/01/2004
16:53:21
| RE: Truck gear ratio - going lower for impro
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This might be too obvious, but why don't you just go down to, say, a 30 inch tire?
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gen1dak
Dodge Dakota
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2/01/2004
17:18:49
| RE: Truck gear ratio - going lower for impro
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Okay, well, if you want to keep the bigger tires, gears are pretty much your only choice. I'd hang in the 3.90-4.10 range. I hope your price includes labor. Even for 2 sets of gears, that's outrageous.
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.boB
Dodge Dakota
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2/01/2004
17:39:57
| RE: Truck gear ratio - going lower for impro
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I think it would be worth swapping gears to a 4.10. Goin from 3.55 to 3.92 will hardly be noticable. You'll raise your rpm range a bit, and lose some fuel mileage. But your torque application will be greatley improved.
But I wouldn't pay $1400. A simple gear swap should cost around $400 per axle, give or take a little.
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2xdakota
Dodge Dakota
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2/02/2004
08:49:57
| RE: Truck gear ratio - going lower for impro
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The price I got was from 4wheel parts installed. the gears where less then the labor to install. I will check around to get a better price, but I want to make sure someone who is good setting up gears does the install.
Thanks
Ken
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jaggy
GenIII
2/02/2004
18:21:01
| RE: Truck gear ratio - going lower for impro
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I installed 4:10's last summer. front and rear diff, + lsd.
my total out of pocket was about $1400.
I love the 4:10's and my mileage actually improved.
I am getting about 2 more MPG both city and highway.
I wish that I would have gone with the 4:56's now!
It was by far the best mod for power to date.
Highly recomend it!
If you want a taste of what gears could do for you do what 99DAK recomends and try some smaller tires.
hope the post helps. good luck
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bobs wrong
Dodge Dakota
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2/03/2004
07:44:20
| RE: Truck gear ratio - going lower for impro
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You will get better mileage with the 4.10 compared to 3.55 for the simple reason you will be able to use o/d!!!
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black2003
Dodge Dakota
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2/03/2004
12:25:49
| RE: Truck gear ratio - going lower for impro
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I did the swap from 3.55 to 4.10. My truck is also 4.7 4x4 auto with the towing package. I love the 4.10. Does great on the hills now. yes it was expensive, but i feel that it was worth the money. I don't do much towing, but acceleration has improved quite a bit, and i can cruise going up any hill.
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2xdakota
Dodge Dakota
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2/03/2004
13:37:52
| RE: Truck gear ratio - going lower for impro
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Thanks for all the input.
black2003,
What did it get your rpm upto on the highway? I run about 2150rpm in OD at 70mph. Also, does the $1400.00 sound about right to you?
Thanks again
Ken
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black2003
Dodge Dakota
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2/03/2004
23:45:14
| RE: Truck gear ratio - going lower for impro
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i have a 2003 with a lower second overdrive. With my 31" tires on i was doing 2150 @ 70mph. Before the 4.10s, i was doing 2000 @ 78. So i noticed a big difference. The cost sounds about right. I also had a lsd put in and my total was $1650
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tobobswrong
Dodge Dakota
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2/04/2004
18:54:06
| RE: Truck gear ratio - going lower for impro
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actually you are wrong, going from a 3.55 to a 4.1 will change the actual final drive ratio by about 20% then the over drive will change it back by about 25 % which in the long run means that your way will actually decrease engine rpm and therefore mechanical advantage by something like 5%, making the engine work harder to produce effectively the same work.
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2BOBorNOT2Bob
Dodge Dakota
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2/07/2004
20:26:59
| RE: Truck gear ratio - going lower for impro
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That is the question.
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.boB
Dodge Dakota
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2/08/2004
19:00:23
| RE: Truck gear ratio - going lower for impro
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Depends on where you live, I guess. My truck has 3.92 gears, and I use OD on the highway all the time. But I generally cruise at 80-85 mph. 4.10 gears would increase my rpm's, and I suspect would decrease my fuel mileage.
If traffic flowed at 50-55mph, then you would probably never get going enough to effectivly use OD with 3.55 gears. It would be even worse while hauling a load or towing a trailer. So lower gears may (in theory) actually increase fuel mileage. Sounds good on paper anyway.
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456
Dodge Dakota
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2/10/2004
21:03:02
| RE: Truck gear ratio - going lower for impro
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Install 4.56 gears. 4.11 will only get you back to where you were originally with the stock tires. If you go to the 4.56 then you can get back some of the performance you lost.
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