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barooka
Dodge Dakota
7/20/2001
21:35:25
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 Subject: 3:55 to 3:93 or 4:11
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I have a 2000 dakota 4x4 w/auto & 3:55 gears. Where can i buy after market rear-end gears? Do you think that it will goof up my shift points or confuse the computer?
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sandman
Dodge Dakota
7/20/2001
22:43:48
|  RE: 3:55 to 3:93 or 4:11
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Message:
4.11:1 are great if you are going to be towing constantly or roch crawling and do not care about gas millage. Dodge designed that package to tow it's max payload with 3.55:1 gears and still get decent gas milage. You will most likely needed to reprogram your ECM and PCM. Your abs system and speed data will not be correct. Yes I think that it is going to goof up your shift points and confuse your computer. You had better change the front R&P gears as well if you ever plan on useing the 4wheel drive.
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Boomer
Dodge Dakota
7/21/2001
18:21:32
| RE: 3:55 to 3:93 or 4:11
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I'm switching mine to 3.73's next week (I hope). I was going to get 3.91's but they didn't make it for my Dana 35 front Diff, so I chose the 3.73's over 4.11. I look at it this way, most muscle car that go 0-60 in a hurry and can still cruise about 100 (not like I really do that, but if Montana ever goes back to no limit...) use the 3.73. Cars like the Vette and Venom use this ratio. I mostly wanted the lower gear for my boat and still get good mpg going on my yearly 1,100 mile trip to FL.
Boomer
97 5.2 4x4
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mbbankk
Dodge Dakota
7/21/2001
18:39:04
| RE: 3:55 to 3:93 or 4:11
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Message:
which is better for mpg?
which is better for performance?
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sandman
Dodge Dakota
7/22/2001
10:33:33
| RE: 3:55 to 3:93 or 4:11
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Message:
The higher the number the more mechanical advantage you get. It also raises your engines RPM for any given speed. If gas mileage is your goal you have to lower RPMs buy useing a smaller number like 3.23:1. You will decrease gas mileage and top speed as you go to a higher number gear ratio but it will make it easier to take off from a stop with a heavy load. You can not increase payload capacity by simply changeing gear ratios. You are limited buy the strength of the transmission, driveshaft, carriers, frame, and crank bearing journals load capacity. I had a corvete motor in a Toyota with 4.10:1 gear ration and I was only geting 4MPG around town and 6MPG on the freeway at 55. I could accelerate real quickly but my engine was screaming at highway speeds.
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Matt
Dodge Dakota
JOIN HERE
8/05/2003
14:39:38
| 3.73's
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Message:
I havea 93 dokata sport manual trans. i want to get a better gear ratio so can accelorate faster should i get 3.73's or what?
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IntenseDak39
*GenIII*
8/05/2003
14:47:43
| RE: 3:55 to 3:93 or 4:11
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Message:
i just put 4.10 gears in my 8.25". You dont have to do anything to the computer.
1998 Regular Cab V6 Auto
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teamfast
Dodge Dakota
JOIN HERE
8/05/2003
18:35:13
| RE: 3:55 to 3:93 or 4:11
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in addition to increasing the rpms, it will run it through them faster! Great for getting the 4.7 up to powerband levels.
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Tracy H
Dodge Dakota
JOIN HERE
8/05/2003
23:11:08
| RE: 3:55 to 3:93 or 4:11
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barooka ... if you plan to lift and/or go to bigger tires, you will definitely want the 4.10 gears. I have 3.55s now and am saving up the $$ to install the 4.10s that I bought. You should be able to get a good deal from Ian, he is selling his brand new 4.10s that he got during a recent group buy. He sold his truck before he got them put in. Check out the following thread:
http://www.dodgedakota.net/boards/raise/1681.html
~Tracy
'00 4x4 SLT QC 4.7 Auto 3.55LSD *My Dak Pics*
3" PA Body Lift, BFG AT 33x12.5 on AE 15x8 149's, Cranked Torsion Bars, Gibson Dual Rear Stainless Catback, Stainless K&N Clone Intake, Jeep H.O. Cams, Removed Clutch Fan & Rubber Flap, Relocated IAT, Powerslot Rotors, Hawk Pads, Autolite 3923, Stant 180° T-stat, ProComp ES-9000 Shocks, Clear Corners, T-Rex Stainless Nerf Bars .....
Mods to be installed: Fastman 68mm TB, 4.10 gears
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Joe E.
Dodge Dakota
JOIN HERE
8/06/2003
00:11:43
| RE: 3:55 to 3:93 or 4:11
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Message:
Question for you guys with 4.10s... Like many of you, I have a V6 in my dak. I am very serious about going to a 4.10 ratio. I had hoped to get them in tomarrow but my travel plans have changed. So maybe in a week or 2. But anyway, I can cruise on the interstate @85mph with like 23-2400 rpms. (I have 31s and my stock gears are 3.21) When I get 4.10s installed, what rpm should I be at going 80mph? Or would it even be possible to go 80mph? lol. Like you Intense. What rpm do you run going around80mph? Thanks.
Joe E.
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IntenseDak39
*GenIII*
8/06/2003
08:13:18
| RE: 3:55 to 3:93 or 4:11
IP: Logged
Message:
well i am running 4.10's with a 26" tire so my effective gear ratio is really 4.47. I am not sure how far off my speedo is off (not more than 3 mph) though because of the tires but i do about 59 @ 2000 rpms. I use to be able to do about 67-68 at the same rpm so it really hasnt hurt it much.
1998 Regular Cab V6 Auto
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Joe E.
Dodge Dakota
JOIN HERE
8/06/2003
14:40:35
| RE: 3:55 to 3:93 or 4:11
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Message:
thanks man
Joe E.
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IntenseDak39
*GenIII*
8/06/2003
16:44:41
| RE: 3:55 to 3:93 or 4:11
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Message:
here's a formula you might find useful when trying to calculate that kinda stuff:
MPH = (RPM x TIRE DIAMETER)/ (FINAL DRIVE x 336)
1998 Regular Cab V6 Auto
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Joe E.
Dodge Dakota
JOIN HERE
8/07/2003
00:20:44
| RE: 3:55 to 3:93 or 4:11
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Message:
Thanks again Intense. A quick question. Final drive=ratio?
And do you feel that your engine is running too high alot? Or do you not find it a problem? Thanks
Joe E.
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IntenseDak39
*GenIII*
8/07/2003
18:54:56
| RE: 3:55 to 3:93 or 4:11
IP: Logged
Message:
engine runs fine.
Final ratio is your gear ratio multiplied by your fourth gear (auto) or fifth gear (manual). For an auto with 3.55 gears it would be:
.69 * 3.55 = 2.4495
1998 Regular Cab V6 Auto
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Joe E.
Dodge Dakota
JOIN HERE
8/07/2003
23:42:20
| RE: 3:55 to 3:93 or 4:11
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Message:
Hey there. Thanks again for yoru info man. Just another question... I jave JasonB here on this site my VIN number of my dak. He looked it up and came back with a bunch of info. He said my truck was listed with a 3.55 ratio. Not a 3.21 like I have always though. Is there a way to test it to find out for sure? It also said I have an "anti spin" diff. It seems that sometimes I can spin both tires over well, but a few times when Ive been in crazy situations with only 3 wheels on the ground, trails in deep holes, I know for a fact that the tire on the ground was idle and the one in the air was spinning like madd. Whats gives? I wonder if I have a stock LS, but it has been outa commission ever since I got it from my grandfather. what do you think>? Later and thx.
Joe E.
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§Mud Runner§
*GenII*
8/08/2003
01:09:24
| RE: 3:55 to 3:93 or 4:11
IP: Logged
Message:
IntenseDak,
As to the formula that u put up there, i have been using it for ages, and it is one of the most useful i think when it comes down to picking tires and gears... ESPECIALLY when building a 4x4. Just a few things for u guys to know bout that bit of math (most of this is pretty obvious, but you wouldn't believe how many times I've seen this thing used wrong..
First, as Intense explains it: "Final ratio is your gear ratio multiplied by your fourth gear (auto) or fifth gear (manual). For an auto with 3.55 gears it would be:
.69 * 3.55 = 2.4495"
This is assuming you are IN overdrive or 5th gear. If you are in 1st, 2nd, 3rd, etc. final drive will be different. More accurate formula:
Final drive=Rear end ratio * Gear-you-are-IN's ratio
I know this is a given but have seen it messed up ALOT..
Second: This is basic math people, but for the ones that are lazy (like me) :-) here is one for getting RPM from specified MPH:
RPM=(MPH * Final Drive * 336)/Tire Diam.
This is useful for seeing if your top speed will only be 60 when you put in those 4.56's lol :)
Third, concerning Tire Diam:
This is in INCHES. Also, you will get better accuracy actually measureing your tires. You will find out that (depending on brand/model) a 36x14.50 tire can really be 35 in. or a 33x12.50 tire can really be 34 in. tall. Don't have to measure though, as you can get the general idea from the stated size
Fourth, Gear ratios: (Automatics)
42RH: 1st gear-2.74, 2nd gear-1.54, 3rd gear-1.00, 4th gear-0.69, Reverse :)-2.21
46RH: 1st gear-2.45, 2nd gear-1.45, 3rd gear-1.00, 4th gear-0.69, Reverse :)-2.21
Have fun people!!!
95 Dakota 4x4 5.2L SLT A/T 3.55's LSD
K&N FIPK
FlowTech Headers
MagnaFlo Hi-Flo Cat
Two Chamber Flows
TransGo Shift Kit
3923's
Accel Cap & Rotor
Mopar PCM
2" Perf. Acc. Body Lift sitting in my room waiting for my next day off.... weeeee!!!!
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IntenseDak39
*GenIII*
8/08/2003
09:45:12
| RE: 3:55 to 3:93 or 4:11
IP: Logged
Message:
Joe,
put the rear of your truck on jackstands and put it in neutral (besure to block off the front tires!). Now get under your truck and look at your driveshaft and put a little mark on it with a marker or chalk. Now have a buddy turn your tire one complete rotation while you count the times the driveshaft rotates. If it rotates 3.5 times, you should have 3.55 gears... about 3 and a 1/4 rotations... probably 3.21
also you can take the diff cover off and just read the number stamped on the ring gear... but thats messy.
1998 Regular Cab V6 Auto
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Joe E.
Dodge Dakota
JOIN HERE
8/08/2003
21:25:04
| RE: 3:55 to 3:93 or 4:11
IP: Logged
Message:
Whats up guys. Yeah I was thinking the tire spin method was the only way other than removing the diff cover. Now I am alittle unsure what gears I should go with. 4.10s or 4.56s. I am hoping to get 33x10.50 on my truck soon. So I think Im gonna hold off on the gears until I can be for sure what tire Im gonna run. Either another 31 or a 33. Do you guys think itd be over kill with a 4.56 gear and 33x10.50, with a 3.9L V6? Thanks guys. Your a life saver. Later.
Joe E.
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IntenseDak39
*GenIII*
8/09/2003
07:10:25
| RE: 3:55 to 3:93 or 4:11
IP: Logged
Message:
well.. you can use that formula to see what gears you would need, or best suit your application.
but i would say that 4.56 would be good with 33"s
Mud Runner,
yeah it works for a lot of stuff. Used it to help put my speedo back to where it should be.
1998 Regular Cab V6 Auto
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