5.9 Liter CR Dodge Cummins 03-07 Discussion of 5.9 Liter Dodge Cummins Diesels with Common Rail Injection

Changing Low Gearing

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Old 10-19-2010, 09:30 PM
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Default Changing Low Gearing

So, I might be going onto my 3rd Dodge, which is an '06 3/4 ton long wheel base quad cab 2wd automatic (base model). The guy who currently has it says he gets 16 mpg and says it could be because it has low gears. The '92 Dodge I got has low gearing and I want to get away from that. Tomorrow, I'm going to try and get a detailed thing by the vin of what that truck has just to make sure because I don't know if the guy is driving mainly city or hwy- they only use it to go to work now.

Have any of yall changed the rear end or gearing because of this? I heard it might be around $1,000 but it would be nice to get the 19-22 mph hwy miles, especially with diesel going up again.

As of now, I'm still leaning more towards going ahead with it and putting up with the low gearing (if it really does have it) until I can spend the money to change it b/c I feel like it's a good deal even though it's a base model truck. It has only 84,000 miles and the guy wants $15,000.

So any opinions, experiences of changing it, etc., would be helpful. This is a big decision for me b/c I'm going to have to sell my Silverado that I love and my '92 Dodge and it probably will put me in a bind until I sell some stuff. My dad and I are going look at the truck in person Saturday since it's a 3 hr. drive- ANXIOUS! Thanks.
 
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Old 10-19-2010, 10:10 PM
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so is this an auto or manual truck.... so if it has low gears they will be 4:11 and for a two wheel drive 16 sounds really low. I get 19 and I drive the **** out of mine sounds like it may have other problems...check that baby over with a fine tooth comb. good luck with a new truck
 
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Old 10-20-2010, 08:06 AM
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ring and pinion change out shouldnt be that expensive.........also as an option you can install larger diameter tires will change thing big time, a 35 inch tire will be equivelent to a gear change
 
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Old 10-20-2010, 01:46 PM
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It's an automatic. Today, I found out it has a 3.73, which they say is mid-range; there's one below that and another above and sometimes you could get 2 above that.

I just looked at ring and pinion set prices and they range from $270-470. Makes me feel much better but that will still have to wait a little bit. When I saw the ad saying 16 mpg, I got worried but maybe it's city driving...I don't know but I believe if I love the truck, everything seems fine, and maybe a little lowering of the price, I'm going to get it.

Thanks!
 
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Old 10-20-2010, 04:13 PM
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i put 4.11s in mine and it was a breeze, and i'm runnin 37" boggers aswell.
 
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Old 10-20-2010, 08:41 PM
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The price of gears isn't too bad. I think they make a 3.42 gear set for the all the AAM axles don't they? Or is it only the 11.5? I would think the truck your looking at would be the 10.5 but I don't know that for sure.

I'm not sure of what the carrier splits are. If you don't have to change carriers you could install the ring and pinion and check contact pattern and backlash and call it good. I would install new bearings while your in there. Setting up the gears can be a bit of a pain. Getting the pinion depth, contact pattern, and back lash set right and jiving with each other can take a while.

Edit: According to Randy's R&P there are no carrier breaks for the 10.5 or the 11.5
 
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Old 10-21-2010, 09:13 PM
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It's a 11.5.

Well, I put a down-payment on the truck after a 3 hr. drive and I'll have the truck here next week when they bring it. I thought it was too good of a deal to pass up. Now, I got to sell the 12-valve, a 4-wheeler, and my Chevy that I will miss so much.

It'll be a while until I buy anything for that truck but the gearing will be the first thing if it isn't a programmer.
 
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Old 10-22-2010, 04:39 AM
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My '06 has an AAM 11.5, but I have the 6-speed manual. Even before the CAI, Manifold, exhaust and programmer, I was getting better that 16, but not by much. An auto will get much better on the highway, my manual does just the opposite getting it's best mileage around town and doing 45 MPH and under, as long as I'm not just waisting time at a stoplight. 16 MPG isn't all THAT bad, as long as he IS refering to city mileage. If you never intend to pull much, and you never see much for slippery roads or two-trackin', I'd gear that 2WD to something way higher than 3.73, which is what my 1-ton 4x4 MegaCab has. Like maybe that 3.42 or at least a 3.55. Wouldn't tow alot with that without beefin' up your tranny, but that's just me. The new 1-ton MegaCab 4x4 on the lot in Fairbanks, Alaska, has 3.42 gearing all the way around! Good luck.
 
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Old 10-22-2010, 04:38 PM
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The only thing it will tow will be another truck on a trailer, 4-wheelers, an offshore boat, or tractor but the average day, nothing...
But here it is as of now: nothing out of the ordinary yet but looks good for the price
 
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Old 10-22-2010, 04:42 PM
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what will you do when you get a foot of snow.
 


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