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Discussion Starter #1
Ok so its order day and I have been going back and forth with this decision. I'm spending big bucks like all of you are too so I REALLY want to get this right.

I commute everyday 30 miles one way + pick-up/drop-off kids at schrool and their various activities. About 21 miles is 2 lane State road then I get into the "city" where I hit 15 stop and go traffic signals (this is not a metropolis type bumper to bumper traffic) in a county of about 80k people. I tow my 29' Jayco BHS (5500lb dry weight) 6-10 times a year on fairly flat or rolling hill terrain (no mountains around here).

Am I good to go with 3.55 gears and save a little on fuel mileage the other 95% of the miles? Am I too concerned with towing for the amount I actually tow? I used to never even care about tow ratings in my 03 GMC 1500 - I'd just hook up the old 4 place enclosed V-nose steel snowmobile trailer and go. It does seem you 3.55 diff guys are getting some mileage #'s above the 27MPG EPA rating (which I'd love to be hitting just for bragging rights) but I hear "some" grumbling here and there from those with 3.92 diff. I will be towing close to the rating with 3.55 and a decent cushion for 3.92.

I so badly wanna join the 30MPG club :cool:

Thanks for the Real World Input
 

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Ok so its order day and I have been going back and forth with this decision. I'm spending big bucks like all of you are too so I REALLY want to get this right.

I commute everyday 30 miles one way + pick-up/drop-off kids at schrool and their various activities. About 21 miles is 2 lane State road then I get into the "city" where I hit 15 stop and go traffic signals (this is not a metropolis type bumper to bumper traffic) in a county of about 80k people. I tow my 29' Jayco BHS (5500lb dry weight) 6-10 times a year on fairly flat or rolling hill terrain (no mountains around here).

Am I good to go with 3.55 gears and save a little on fuel mileage the other 95% of the miles? Am I too concerned with towing for the amount I actually tow? I used to never even care about tow ratings in my 03 GMC 1500 - I'd just hook up the old 4 place enclosed V-nose steel snowmobile trailer and go. It does seem you 3.55 diff guys are getting some mileage #'s above the 27MPG EPA rating (which I'd love to be hitting just for bragging rights) but I hear "some" grumbling here and there from those with 3.92 diff. I will be towing close to the rating with 3.55 and a decent cushion for 3.92.

I so badly wanna join the 30MPG club :cool:

Thanks for the Real World Input
I have 3.92, 20" wheels and slightly over sized tires and on the flat sections of road that are posted between 40 - 50 MPH I am getting a little over 30 MPG. My RPM's are around 1500 during that speed.

Those stop and go traffic signals really kill my tank average MPG. But learning to use the transmission with a little less pedal pushed my MPG creeps back up a few clicks. The MPG screen on the dash is a great tool for learning this.

I would guess that the 3.55 would have no issues towing, controlling and stopping a trailer load of 6500 lbs. With a 3.92 it is going to give you more towing cushion for the unknowns.
 

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I just bought a ED crew, 4x4, short box 1 monh ago, already have 4k km's on her.
I went with the 3.55 gears. My commute to work is 1hr each way and I will tow about 7k a dozen times or so a year.

Thus far, my commute to work has resulted in about 28MPG and when towing that 7k, about 19mpg.

For me, 3.55 was the right choice.

Paul
 

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I towed a 5000 lb dry weight keystone zeppelin travel trailer 400 miles in rolling hills with about 250 pounds off wood in the bed. Was very happy with the trucks ability to handle it. For what that's worth....

Mine is a limited, 4x4, 3.55's, 20's with 305/55r20 terra grapplers
 

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My view is you will be fine with the 3.55. Some forum posters complain about the amount of shifting the truck does. I find that the transmission is so smooth, the upper gears so close together and the vehicle so quiet that I hardly notice the 6, 7 and eighth gear shifts up or down. The tow/haul mode reduces the amount of shifting too. You didn't mention the distances you tow but it sounds like it is probably within a couple hundred miles each way or less so it isn't much in total. The main difference between the two when towing is the 3.55 will be a bit slower in the 0-15 mph speed but after that it will just stay in the lower gears a bit longer and feel about the same.

All the best, you'll love the truck.
 

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So I had a similar question which was "if I can tow 1000lbs more with the 3.92s than I can with the 3.55 and all I lose is 1-2mpg, why would I ever consider the 3.55s"? I received two replies. This being the first.

ROBERTM--3.92 rear end doesn't magically give you an extra 1000 lbs of capacity in real life. There are no other additions to the box frame, suspension, brakes, cooling equipment etc. It just allows you to maintain a certain speed going up a certain gradient hill with 1000 lbs more load than the 3.55 rear end.



Basically if you have a hill and a trailer weighing X lbs the fastest the 3.55 truck will be able to make it up is 60 mph while maintaining whatever fluid temperature parameters Ram decided upon. Take the exact same example but with a 3.92 truck then your load will be X+ 1000 lbs and you will still get up there at 60 mph.



So, if you want to take that load x plus 1000 lbs up the hill with 3.55 truck you will either: A) Simply not have the power to get there at 60 (Maybe 55 mph) or B) Need to slow down to 55 to maintain reasonable fluid temps.



The only REAL hard and fast weight limits are axle and tire load. All other numbers are guidelines which can be exceeded with proper setup, proper speed and proper attention to the trucks diagnostics.



Opinions may vary ;)
 

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This is the second...

SRFRACER42--There are a couple of reasons to prefer the 3.55s. First, the additional 1000# may not add any actual utility for you. 1,000 lbs sounds like a lot, and it is. But, bigg(er) picture, 1,000 pounds is a 7% increase on top of a 13,500lb combined gross. The difference between towing at sea level and towing at 8,000 ft elevation is more than 7%, hauling through mountains vs towing in the plains is a lot more than 7%. Many owners are comfortable running at or slightly over the GCVR -- they operate the truck in a manner they feel is safe, and the drive train delivers adequate power for them. On the other side of that spectrum are some very reasonable people who would tell us all that if you're towing 7,500lbs or more on a consistent basis, you should be in a 3/4 ton truck anyway. The 1/2 ton is already compromise, less capability for more comfort and better mileage. The 3.55 is for many people a better compromise than the 3.92.



I ran waaay too many numbers before making my selection and purchase. I know intellectually that I don't need the 3.92s, but it gives me a warm fuzzy feeling inside knowing my truck has the extra towing rating. Some other folks get a warm fuzzy inside knowing that their truck is getting the extra MPGs, whether or not the money they save is material, its something they take pride in. In the end, our purchases (for most of us anyway) are all about that warm fuzzy.



I like the 3.92s. If you're leaning that way, and want a rationalization, Spur has an outstanding argument. Maybe you'll spend an extra $200/year on fuel, call it $15/month. Negligible in the context of your fuel bill, maintenance, depreciation and (for most of us) interest. Get the 3.92s, and skip the trip to Starbucks a couple of times a month. Tow with confidence, and enjoy the extra oomph you'll have from each stop light around town.



If you're leaning to the 3.55s, and want a rationalization, there've been several excellent ones. The 3.55 can, practically speaking, do pretty much anything the 3.92 will do, and you really will get THE best mileage in any full size truck, especially while towing (when those gasser turbos are just gulping fuel). Are you really going to tow 9,000 lbs with your 1/2 ton? If not, why do you need the 3.92? If you are, why are you towing in a 1/2 ton
 

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Discussion Starter #9
I may have been talked into 3.55!! The wife wants to take a few long trips in the next few years. One to N Carolina (so some mountain towing thru Appalachia) and possibly Minnesota S Dakota area with the kids. But normally I travel no more than 100 miles around where we live. Some trips to the UP now that I have a decent tow vehicle on its way
 

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I may have been talked into 3.55!! The wife wants to take a few long trips in the next few years. One to N Carolina (so some mountain towing thru Appalachia) and possibly Minnesota S Dakota area with the kids. But normally I travel no more than 100 miles around where we live. Some trips to the UP now that I have a decent tow vehicle on its way
Congratulations. For what its worth, not much actually, I think you made the best decision for your described usage! You'll love the truck.
 

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I tow and like the idea of having the extra tow rating of the 3:92 gears. I just did a 2138 mile trip, towing a 1,200 tent trailer (gave the tent trailer to my son) for the first 1,000 miles, the rest of the trip was without the trailer. My mileage was 27.4 mpg for the whole trip, pretty good for a full size 4x4 truck.
 

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I struggled with the same decision until order day. I was advised by several guys in the know that occasionally towing an enclosed motorcycle trailer a couple of times a year doesn't warrant the 3.92 gears. So I took the 3.55 route. I don't have the truck yet. Hopefully by the end of next week.
 

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Discussion Starter #13
I struggled with the same decision until order day. I was advised by several guys in the know that occasionally towing an enclosed motorcycle trailer a couple of times a year doesn't warrant the 3.92 gears. So I took the 3.55 route. I don't have the truck yet. Hopefully by the end of next week.
I pretty much ran thru that same logic today! Thank you for the reinforcement of my decision.
 

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One other thing to consider is your driving style and normal Interstate travel speeds. When I ordered mine I only planned on towing a small motorcycle trailer (about 2,000) pounds loaded from NY to FL and back for winter. I didn't "need" 3.92's for this load but I plan to drive at about 70 mph and I wanted the engine to be at the torque peak or slightly over (1800-2000rpm) at that speed. My thinking is that If I come to a hill locked up in 8th gear at 2200rpm, torque will increase as the engine slows a little and most hills will be pulled without a downshift to 7th. I'll let you know in November whether my theory works in practice.
 

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@CB919 - read my "1st tow report" with my Lance 2285 trailer... i was like you and Spur - back and forth (initially thinking i HAD to have 3.92) - you will be fine. you will be MORE than fine with 3.55 - do not remotely think back on the choice - 3.55 is going to do what you need and give you plenty to smile about. enjoy your new truck when it arrives!
 

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Discussion Starter #17
@CB919 - read my "1st tow report" with my Lance 2285 trailer... i was like you and Spur - back and forth (initially thinking i HAD to have 3.92) - you will be fine. you will be MORE than fine with 3.55 - do not remotely think back on the choice - 3.55 is going to do what you need and give you plenty to smile about. enjoy your new truck when it arrives!
I did read your report and it was very informative. I really tend to over do things and try to be conservative. Glad that you feel confident in the 3.55 choice and I think in my scenario it will be the best situation.

And to think I passed on a white SB with bench seats and 3.55 in my area on the lot a few weeks ago? It didn't have trailer tow package and i really wanted the LB and prairie Pearl paint job. Too much to compromise.
 

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I would think that towing up to around 5,000 lbs on mostly highway miles that are not at altitude a 3.55 would be the ticket for me.

Go to altitude above 5000 feet and with the same load and same driving conditions a 3.92 might be better for me.

In town towing at 35 - 50 MPH with 5000 lbs at altitude or not a 3.92 would be better with after market LT 20's tires would be better in MPG than any 17's.

Towing less than 4,000 lbs in any condition, a 3.55 would be better for me.

Towing a reasonable amount above 6,000 lbs often in any traffic and highway condition I would go with 20's, after market LT tires and a the 3.92.

85% of my towing is around 5K lbs in mixed driving not exceeding 50 MPH. 5% around 8K lbs over short (7 miles) but hilly terrain not exceeding 50 MPH and 5% towing less than 4000 lbs not exceeding 60 MPH.

Again I have LT tires that are rated at over 3K per tire.
 
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