misterKTM

Brief history...Been pulling a 26 foot tongue trailer for years..2003 single rear wheel 3500. Works great - no complaints. Looking at upgrading to a seriously large fifth wheel..like 40 feet, 18,000 pounds..3300 on the fifth hitch. Thinking I may want to convert my truck (don't want to buy a new one) to a dually. Thoughts ?? Is it necessary ? So that's my first question..interested in opinions of my single rear wheel towing a mammoth as described.

Secondly - if I do convert my truck to a dually...I'm thinking all I need is new wheels and a bed. Wouldn't my rear end, suspension and all that be identical ??? The most I could see needing to change is possibly putting longer wheel studs in ?? Anyone have any experience or knowledge along that sort of conversion ?

Lastly...again assuming I do conversion...I really like the newer dually box's with the molded rear fenders - they just kind of gradually slope out instead of looking like an additional bolted on fender on the outside of the standard box..so, what year did they start making the slick looking box's? And what are the odds that one of those will bolt onto my '03 chassis ??

thanks for any input.

Dieselbuilder

If you are looking to go to a 40' fifth wheel UPGRADE to a new truck, 3.73 are to tall you will need 4.11 for that much weight the money you will have to spend to change yours over it would be cheaper to buy one and you would have to re-register you truck for a one ton it may hot be possible in your state?

misterKTM

It's already registered as a one ton....it's a 3500 srw. I believe 3.73's will be just fine, not worried about gearing at all. But thanks for your thoughts.

NE frmhnd

Be more stable. You might check that your truck can handle that hitch weight as is. Only need to change the combination registered weight if so.

pind

When towing heavy, there is nothing that compares to the stability offered by the trucks with training wheels.

Even for day to day driving, other than slippery conditions, the dually is just more "planted" on the road. Less sway and wander. I am no expert on this stuff, I own srw and drw trucks, have run both while towing, and both as body job service trucks. Each has its place, but for the bigger jobs, use the bigger setup.

johnh

when i converted mine to a 2w, i really couldn't tell much difference other than fuel mileage when not pulling the fiver

FiverBob

Had a srw when bought present fiver, 16,000 pounds. It had 3.73. Went to drw, 4.10 - - no comparison on how much better it towed and much more stable. All this on the same rig - - gave me a good comparison. I was sold.
Bob

misterKTM

good reply's thanks. I like your perspective fiverBob. You have the same truck as me. I still don't think the gear change did anything for stability, but I'm sure it helped steep hill starts.

anyone have any details on the parts needs to do the swap on an '03?

FiverBob

One thing people miss on the axle ratio is normal running speeds. I do not push the speed with that big rascal on behind me. I can still run in 6th gear many times on the highway that would require downshift with 3.73. I am not pushing it to maintain, hence I get great mileage. In the mountains, I do not have to downshift as soon as I did previously. I just got home from 3-1/2 months in Alaska. My average for the 14,000 miles was 13.3 - - not too bad for 24,000 pounds.

Jeff in TD

With the stick shift, I think you will be ok with 3.73.

I had an 03 3500 SRW and a 30' 5th wheel toy hauler.

When I decided I wanted the 40' version, I knew it would overload my rear tires, so I got an 06 dually.

I towed the same 30' rig with the dually before I found my big 5th wheel.

The SRW handles the 30' fine, but I found after hauling it up a curvy narrow mountain road I arrived ready to ride when I towed with the dually. With the SRW I'd be wanting to rest first.

Bottom line, even with a moderate size 5th wheel, a dually is just more planted, and relaxing to drive.

HMX-1

If it's a 4x4, the front end and rear end need to be swapped to the same gear ratios. You can't just do the rear because if you try to use 4WD the gear ratios are off.

You'll also need a new bed (or source a good used one) and the entire rear axle. The DRW axles are shorter to accommodate the extra two tires.

The brakes I'm not sure about, but there's a chance you'll need them from the DRW axle as well. If you could find a DRW truck that an insurance company "totalled" but is still sound mechanically this might be a better choice.



-Kris

cLAYH

For the front axle you can just bolt on the adapter provided its the same gear ratio as the new rear axle. No need to swap the whole axle unless changing ratios. Which I strongly recommond if you don't already have 4.10s.

Current box can be used by opening up the wheel wells and installing the dually flares.

Jeff in TD

A buddy converted a 2nd gen. I don't think he changed rear axles, but may have bought wheels with a special offset for dually conversion.

For me, finding a clean Laramie stick dually and selling my SRW was a pain, but made the most sense.

gasjr4wd

There are some factors that come into play. I don't see the 26' weight. I'll guess 6,000lbs. There is a big difference in a bumper pull and a 5th wheel/gooseneck. Moving the weight does wonders. Some tires are much designed better for towing and highway use. Get a firm sidewall tire rated for the most you can get. Mine are rated around 4,000lbs each and I notice a big, big difference from what was on it. They were still rated same in load range but the old ones were around 3,100lbs. Then there are the guys that swear by adding a rear anti sway bar or air bags it helps also.
You don't say how often you are going to be yanking this thing around, on what type of roads, your driving style, etc. It looks like you have your truck the way you want with all your added goodies. I don't know about your state, but here they go by the actual GVW. IIRC our trucks are rated at 9,900lbs. The Dodge 03 3500 dually is rated something like 11,000lbs I think. Now these numbers are a guideline for us users, but to the law it is what it is. Get pulled over and sent to a scale and you may be screwed. I would do it the 18,000lbs with mine and not think too much about it. Are you going to be towing with full fresh water tanks? Fully loaded? Most people don't so that 18,000 maybe much less. The ones I've seen, dry is around 12,000lbs.
With all that said, if you are going to be towing this thing a lot, you should really think about selling your truck and getting a dually. If you are asking, that should tell you. Don't try to convert. Using a converted truck with wife & kids in it... Rather than ask this list check RV forums. I see they all will tell you the truck should be a 4500+. I've looked.
Oh, the funny thing is my neighbors 06 F250? Rated 10,000lb gvw vs our 03 3500 9,900lb gvw. Go figure.

RobG

I have a dually (6sp) and tow a 40' 5th wheel toyhauler. My gross combined weight starts at 23k and has been as high as 25k. With my South Bend Con-OFE clutch, I wish I had 4.10s every time I tow. Don't get me wrong -- the clutch rocks. But if you have to start off from a dead stop with anything resembling uphill (even SLIGHT), it's very hard to get the truck moving without slipping the **** out of the clutch, which is hard to do with a South Bend in the first place. The truck tends to buck pretty bad til you can get moving fast enough to get into 2nd gear.

Mine has the G56 tranny, so it has the extra-short 6th gear, which I think is why 4.10s weren't an option on these trucks. My 2001 (NV5600) had 4.10s and it was a great tow vehicle, except that I _hated_ the transmission because shifting it was about as imprecise as you could get.

So... if you're 100% stock, you'll probably be fine on 3.73's. If you're modded or have a somewhat grabby aftermarket clutch, just take it easy from stops.

Rob