4x4 3.92 rear
Professional
Joined: Feb 2009
Posts: 148
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From: Fairmont, WV
I've never seen above 16 with mine. Of course, I've never had it on the interstate farther than 50 miles or so and even ion the interstate in WV there are no flat stretches. I've had 245/70/17's up to 285/70/17's and it really made no difference in my fuel economy.
Rookie
Joined: Jan 2005
Posts: 99
Likes: 0
From: Vermont
Does the 09 have the MDS system?
Record Breaker
Joined: Jan 2010
Posts: 1,400
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From: San Pedro, California
Yes the do have the MDS. I have the 09 CC with the 3.21 axle. We have a property in the mountains but live by the ocean. On the way there the lie-o-meter says we get close to 20 MPGs but hand calculated it's usually about 1 MPG less. On the way back we get closer to 21 on the lie-o-meter but hand calc about 20. This is all highway but sometimes leaving the city we get some traffic and that hurts the MPGs some. I usually like to pass freely and then set the cruise control to at least 75 MPH. When my wife drives the truck, she drives closer to 70 and gets about 22 MPG on the lie-o-meter. Around town with lots of stop and go it closer to 13 MPG. The truck is completely stock. The drive each way is 330 miles.
Administrator
Joined: Jul 2007
Posts: 24,686
Likes: 21
From: South Georgia/East Florida
very interesting! I have driven a few 3.55's but have not driven the 3.92 yet. I am very surprised that someone has said that the 3.92 will do better around city driving. I am in Mobile, Al. and the city driving is horrible. I get 13 miles a gallon in my V6 Dakota. Is it a much more noticeable difference with towing. I realize it makes the truck go from an 8550 capacity to 9950.
How come I was advised by our local RAM dealership that front and rear axle ratios don't have to be the same???Me not using 4 Wheel drive is like asking the pope not to pray
I am really confused now as my RAM, and according to this same dealer, originally came with 2 different axle ratios
Whoever you are talking to at the dealership seriously needs to find another line of work. My 14 year old niece knows you can't have different axle ratios front to rear on a 4x4!
It's a 2011 Ram 1500 Quad Cab SLT 4x4 HEMI 5.7, 5speed Auto transmission and 17" rims.
I was told that my front diff was a Chrysler 9.25" & @ the rear I had a Chrysler 10.50". I did some research and found out that the Chrysler 10.50" had 14 bolts, while mine has 12 bolts that I counted....Weird!!! Can't I type my vin number somewhere and have the list of equipment popping out?
I was told that my front diff was a Chrysler 9.25" & @ the rear I had a Chrysler 10.50". I did some research and found out that the Chrysler 10.50" had 14 bolts, while mine has 12 bolts that I counted....Weird!!! Can't I type my vin number somewhere and have the list of equipment popping out?
First of all NO 1/2 ton truck comes with a 10.5" rear axle. Secondly, the Chrysler Corporate (AAM) axles were not used after the 2010 models as Ram switched to ZF for their axles, but sizes still remain 9.25", 12 bolt, 31 spline. The front is an 8", 10 bolt, 29 spline.
The ONLY 1500 series to have a 10.5" rear axle is the MegaCab. Also, there is NO dealer option to order a half ton Ram with an axle ratio other than 3.21, 3.55 or 3.92, they can not order you a 2011 half ton 1500 Ram with 4.10 axles from the factory.
RAMs were offered with 3 ratios, 3:55, 3:73 and 3:92. You chose one which matched both the front and rear in a 4x4. I believe you are being far too literal.
The front housing is likely only big enough to fit a 3:92 while the rear can fit a 4:10. That said, the front a rear need to match which leaves you with the ability to only go so low as a 3:92.
The front housing is likely only big enough to fit a 3:92 while the rear can fit a 4:10. That said, the front a rear need to match which leaves you with the ability to only go so low as a 3:92.
Not sure of the ZF carrier but I know for a fact that the 2009 & 2010 1500s with AAM axles could handle up to 4.88 in the rear and 4.56 in the front housings which would mean max for a 4x4 would be 4.56s...
Last edited by HammerZ71; Nov 10, 2011 at 11:59 PM.
Registered User
Joined: Oct 2011
Posts: 12
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From: Planet earth
Well then I guess I should have ZF axles in my truck...Can't we just put the vin number somewhere on the web and get "The" list of equipment the truck came out from the factory with?
Anyway the dealer announced that as of next week, the parts I ordered will start arriving
Mopar Ram Runner body kit + stage one 3.5" suspension lift kit + the famous 4:10.1 axle ratios + Pro Comp Black 17"x9.5" rims + 35x12.50R17 BF Goodrich MT KM2.
I will take a few pictures of my front and rear diffs and upload them here, hoping that you guys could identify them for me, coz if they can't both hold the 4:10.1 ratios, this means that either they took me for a dupe and will be installing 3:92.1 ratios, or after market parts that are not original...
Both cases I will be f....d
Thank you all for your help
Anyway the dealer announced that as of next week, the parts I ordered will start arriving
Mopar Ram Runner body kit + stage one 3.5" suspension lift kit + the famous 4:10.1 axle ratios + Pro Comp Black 17"x9.5" rims + 35x12.50R17 BF Goodrich MT KM2.
I will take a few pictures of my front and rear diffs and upload them here, hoping that you guys could identify them for me, coz if they can't both hold the 4:10.1 ratios, this means that either they took me for a dupe and will be installing 3:92.1 ratios, or after market parts that are not original...
Both cases I will be f....d
Thank you all for your help
Administrator
Joined: Jul 2007
Posts: 24,686
Likes: 21
From: South Georgia/East Florida
http://www.dodge.com/webselfservice/...m%28%27R%27%29
You can also request one from your dealer and they can print it on the spot...
Registered User
Joined: Oct 2011
Posts: 12
Likes: 0
From: Planet earth
Many thanks dear HammerZ71 I got the specification sheet printed, and I got a picture of the rear diff wide open as well...It's a 12 bolts is for sure
Usually there should be a tag or something on the diff covers, mine has nothing at all
DRNS 235mm rear axle which is 9.25" like you guessed, and DJMS 205mm HD front axle which is 8". DS7S Conventional Differential Frt Axle.
Is it a ZF, an AAM, nobody knows
Nothing written about the ratios on that paper we printed, unless we didn't know what to print)
Are we on the right track in determining whether a front+rear 4:10.1 axle ratios is feasible?
Usually there should be a tag or something on the diff covers, mine has nothing at all
DRNS 235mm rear axle which is 9.25" like you guessed, and DJMS 205mm HD front axle which is 8". DS7S Conventional Differential Frt Axle.
Is it a ZF, an AAM, nobody knows
Nothing written about the ratios on that paper we printed, unless we didn't know what to print
)Are we on the right track in determining whether a front+rear 4:10.1 axle ratios is feasible?
