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3.21 gear set? #1928200
10/08/15 07:23 AM
10/08/15 07:23 AM
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Kentucky
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dfsmopars Offline OP
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What are the thoughts on a Ram with 3.21 gears in a four door, 4x4, with either a 6 speed or 8 speed trans behind a Hemi? Talking 2013, 2014 or so years. The objective is fuel economy but not a dog. Rarely pull a trailer but on occasion could hook up an open car hauler with a 2 ton car. Current ride is a '02 5.9 quad cab with 3.55 gears. I like the '02 but tired of the poor fuel mileage, cracked dash and rust.


‘72 Charger, 5.9 Magnum, Tremec 5 spd., Pro-Touring
‘14 Big Horn, Quad Cab, 4x4, 1500
Re: 3.21 gear set? [Re: dfsmopars] #1928215
10/08/15 09:35 AM
10/08/15 09:35 AM
Joined: Nov 2008
Posts: 5,946
Greenville, PA
redraptor Offline
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I think getting away from that magnum to a newer Hemi is a huge step in power and mileage. twocents

Re: 3.21 gear set? [Re: dfsmopars] #1928277
10/08/15 11:51 AM
10/08/15 11:51 AM
Joined: Oct 2006
Posts: 7,358
Iowa
burdar Offline
Owen's Dad
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Iowa
I've got a 14 quad cab 4x4 with the 3.21 gears and the 8-speed. I haven't towed anything with it yet. My only complaint is the huge throttle response lag that's built into the drive by wire system. It's really annoying. I try to get the best mileage I can when ever I drive it. This summer I saw 25.7mpg on the digital display driving from Iowa to Chrysler's at Carlisle. It gets great mileage at sustained 55mph speeds. It really starts dropping off above 60mph.

Normally, while driving to the Mopar Nats(with my other vehicles, I have to stop for gas in Crawfordsville.(west of Indy)I didn't stop for gas on the way to Carlisle until I was east of Indy. Even then, I stopped because I was tired and needed to stretch. I could have made it all the way to Columbus on one tank of gas. I saw 25.7mpg on the display when we were driving 55mph in Pennsylvania, before hitting the turnpike.

Re: 3.21 gear set? [Re: dfsmopars] #1928333
10/08/15 01:28 PM
10/08/15 01:28 PM
Joined: Jan 2003
Posts: 4,696
enfield, CT
ViperDave Offline
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enfield, CT
I have a 2014 tradesman crew cab 5.7/8spd 3.21 on 35" tires.

Just towed a 90 d250 cummins truck about 70 miles last week on an open steel deck trailer. Power was fine, trans temp and oil temp stayed right where they normally are, did about 70 mph up and down the hills.

image1.JPG

67 Dart GT Vert 273/904
72 Town & Country 440/727
90 D350 reg cab dually cummins
15 Scat Pack Challenger
Re: 3.21 gear set? [Re: dfsmopars] #1928388
10/08/15 02:49 PM
10/08/15 02:49 PM
Joined: Jan 2005
Posts: 12,408
Kalispell Mt.
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HotRodDave Offline
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Kalispell Mt.
Mopar claimed about 10% better miledge when they came out with the hemi, of course the trucks got huge-er at the same time. The wind drag from being so huge is going to hurt MPG as the speed goes up. I would not worry about power with the 3.21 gear as they dropped 1st gear ratio a lot also so take take off TQ will still be more you just get a better final drive ratio by having the higher rear gear.

One time I re-built one of those 5.7s for an 04 ram that coughed out a rod for no reason and we degreed the cam (stock cam we degreed mostly out of curiosity)and decided we should advance it one tooth and holy moly throttle response was waaaay better after that! I do not remember the numbers we came up with but figured it could only help and boy did it, the thing is now hyper responsive. We did end up with a CEL for cam/crank correlation or something similar but that truck is very responsive and quick for a 4 door 4x4. That was pretty much the only mod on the truck besides a crappy dual exhaust installed by previous owner. Really makes me want to put my 5.7 in my dakota but I already lose sleep worrying about the wiring.


I am not causing global warming, I am just trying to hold off a impending Ice Age!



Re: 3.21 gear set? [Re: dfsmopars] #1928433
10/08/15 03:44 PM
10/08/15 03:44 PM
Joined: Jan 2006
Posts: 8,162
USA
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360view Offline
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3.21 should be fine on a 5.7 with variable valve timing and an 8 speed trans.

I changed from the factory 3.55 to a set of NOS 3.21 gears when i had to have pinion bearings replaced at 65,000 miles on my 1995 Ram 5.9 V8.

MPG went up by 1 at a steady 60 mph on an unloaded truck.

3.21 diff in 2nd gear ratio of 1.45 on the 46RH actually is a better towing hill climbing ratio.
It would be even better if the TCC would lock up.

3.21 diff with 1.00 third gear ratio gives slightly better MPG on the highway

But 3.21 with 0.69 overdrive while towing is an even worse chance to take than overdrive towing with 3.55

Re: 3.21 gear set? [Re: dfsmopars] #1928856
10/09/15 08:00 AM
10/09/15 08:00 AM
Joined: Aug 2007
Posts: 2,356
Kentucky
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dfsmopars Offline OP
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I have yet to find a Laramie model with an 8 speed. Did they make them for 2013 or 2014? All the trucks I have seen so far are six speed console shifts.


‘72 Charger, 5.9 Magnum, Tremec 5 spd., Pro-Touring
‘14 Big Horn, Quad Cab, 4x4, 1500
Re: 3.21 gear set? [Re: dfsmopars] #1928892
10/09/15 10:31 AM
10/09/15 10:31 AM
Joined: Jun 2008
Posts: 1,822
Colorado
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denfireguy Offline
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Originally Posted By dfsmopars
I have yet to find a Laramie model with an 8 speed. Did they make them for 2013 or 2014? All the trucks I have seen so far are six speed console shifts.
2013 and a half or about February, 2013 is the best I can determine 8 speed availability. That is what I found when I was looking for mine. Did find a 2013 with an 8 speed but two days later found a 2014 so I bought it instead. The truck had only 3000 miles on it. As far as I know, all 2014 Laramies have the 8 speed. As you probably know, the dash selector knob is the tip off.
Craig


2014 Ram 1500 Laramie, 73 Cuda
Previous mopars: 62 Valiant, 65 Fury III, 68 Fury III, 72 Satellite, 74 Satellite, 89 Acclaim, 98 Caravan, 2003 Durango
Only previous Non-Mopar: Schwinn Tornado






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