Which gear ratio to get?

[MoparToYou]

I'm in the process of ordering an '02 Dodge 3500 QC 4x4 with the H. O. motor, and six speed trans. I've picked all the options and the color I want (Graphite Metallic sport package), but haven't decided on the axle gear ratio. The truck will haul a 3200 lb. Lance cabover camper, while pulling a 7,000 lb auto transport trailer, and will be used primarily in Nevada, Utah, and Colorado. I've told the dealer to go ahead and order the 3. 55 gear ratio unless I tell him otherwise by this Thursday, which is when I told him to place the order.



So should I get the 3. 55 or the 4. 10?



Thanks for your help.

 

[JSchooley]

Get the 3:55. The 6SP has evenly spaced gearing and still tall in 6th. I would like a little lower ratio when dry. I keep trying to shift into 7th when I hit the freeway, listening to the engine I think there is one more to go.



With your load you should be able to cruise up 6% at 65+ MPH in 5th with throttle left over. I'm pulling 12000+ lb billboard and had to seek 4th very few times in my last trip of 4,500 miles out West.



BTW - I Love the 6sp HO.

 

[Archive]

Ok, here is my opinion...



I would get the 4. 10s... the sweet spot for towing is 2000-2200 rpm. This puts you at about 62-63mph. Maybe faster, since they now come with the 235 tires.



I believe that with your load, that speed will be plenty fast. I always cringe when people with loads drive too fast. When empty, I have cruised easily at 72mph, which is about my limit due to many tickets in my younger days.



If you like higher speeds, go with the 3. 54s. If you like slower speeds, go with the 4. 10s. You should be looking to tow in the "sweet spot".

 

[MikeR]

I agree with Rob,get the 4:10's. You are obviously going to haul quite abit of weight. Of course the 3. 54's will work,any gear will with a diesel,but your engine is going to have to work a bit harder because it's not going to be in the 'ideal' sweet spot. This will make your EGT's run higher which will make you burn more fuel compared to a truck with 4:10's.

The newer trucks with those taller 235/75/16 tires don't make the engine spin as high an RPM as the older models did.



-Mike

 

[Barry]

4:10s. Dually, 4X4, load factors and the area in which you operate, PLUS, it you ever intend on using a larger tire. 2125 RPM = 65 MPH

 

[Rcpilotlv]

I would get the 3. 54 Ratio. With the high output you will be able to tow anything you want at anytime. With that six speed all you have to do is use those gears. Thats what makes this truck so nice. Not to mention you will get better miles per gallon. I think 4. 10 ratio is to low for everyday driving, more rpm means more wear and tear. Just my opinion. Cant wait tell my 2002 is in!

 

[Archive]

Read this for more info on gearing choices!

 

[MoparToYou]

First of all let me say THANK YOU to all that helped out here. This forum is a great resource.



I went with the 3. 54 gears, and here is why. The 3. 54 gears will work great for every day driving, and work ok for most of the towing I do. The 4. 10s would have worked better for most of the towing I do, but for one trip each year they just would NOT have worked at all.



Once a year I join a group of local four wheel drive enthusiast for a trip to the Rubicon Trail, which we enjoy driving with our Jeeps. We don't bring the campers for this trip, because we camp out on the trail instead of at the campground. I would therefore be towing a 3,000 lb. trailer with a 4,000 lb. Jeep on it. The trailer is a bit on the overkill side, as it is rated to carry 14,000 lbs. , has eight lug wheels, 12 ply tires, and huge electric brakes on both axles. The trailer doesn't even realize it has a load yet, with just the Jeep on board.



Anyway, ... the group I go with thinks this annual trip is a 1900 mile long drag race, and includes one person that owned a Chevy dually with a supercharged 454 big block; however, this person now owns a new Chevy dually with a Duramax diesel. Another person owns a Dodge Cummins 12 valve with extensive mods, claiming >900 ft. lbs. torque. Another person owns a Phord Powerstroke that is heavily modified as well. As for me; when this all started in '97, I owned a Phord Expedition, and got smoked really badly on these trips. In '98 I bought a Dodge dually V-10, and still got smoked, but not nearly as badly. And believe it or not the Dodge V-10 got better gas mileage towing than the Phord Expedition did (6. 0 vs 5. 3 mpg). I really revved the snot out of that Expedition while trying to keep up .



Now it is '02, and it is time for me to step up to the plate, so to speak, with the purchase of a new truck. I'm starting with a Cummins H. O. , and may eventually add injectors, 4" exhaust, and an add on computer module, but will likely stop at the 750 ft. lb. stage.



Rob Hanson's comment that I should get the 4. 10 gears if I want to tow at 62 to 63 mph was a real eye opener. These guys tow at 90 to 100 mph across those deserted highways in Nevada. I'm going to need the 3. 54 gears to keep up it would appear, so that is what I ordered. Maybe new friends would be cheaper than a new truck .



Go ahead, tell me I'm irresponsible. I deserve it.

 

[Rcpilotlv]

Hey Mopar, Sounds Like you really need a VIPER!

 

[COBRAJET]

I would choose the 4. 10's if you are going to be towing a lot with that combo... especailly in CO. The 4. 10s let the truck stay in 6th gear most of the time turning less RPM's than the same speed in 5th gear in a 3. 54 geared truck. The higher axle ratio also helps going through the gears. The truck will pull better out of the upshifts with the 4. 10's. I gross right at 22K towing with 4. 10's in a PSD and it tows great in CO. It will stay in OD up a lot of the frewway passes and pulls strong in drive up the narrow ones. I towed the same trailer with the Cummins last weekend. It had plenty of power, but did not accelerate as well as the 4. 10 geared truck. I will attribute this all to gears... the power is the same and the PSD combo weighs more... . CJ

 

[Cooker]

IMHO. With a manual transmission 3. 54's are the way to go. Unless you are going to run larger then 33" tires then you may be better off with 4. 10's.



-Ryan

 

[klenger]

MoparToYou:

I work for Learjet. Maybe you need to talk to our sales dept. 1-800-buy-lear. Burns Jet-A instead of Diesel #2, climbs real good, and can haul quite a bit. Good luck.