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Upgrade rear axle for F250 SD

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Old 04-18-2011, 12:51 PM
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Upgrade rear axle for F250 SD

I have an 2006 f-250 super cab with 6.0 and 4X4 with a 3.73 rear end.
I am wanting to increase the towing capacity of my current truck. Looking at the towing charts for 250, 350 SRW, and 350 DRW, the only difference I see is the rear axle. The engine and transmission are the same I believe. (Correct me if I am wrong.) Is there an aftermarket axle that I can buy to increase my towing capacity? I do realize that the towing limits are not just dependant on the engine or transmission. Buying an axle is cheaper than buying a new truck (I hope).
 
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Old 04-18-2011, 01:08 PM
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From everything that I've read the real problem is the GVWR number on the inside of the door post. You could change all the parts for your truck to be an F650, but if that tag doesn't change, and it can't as I understand it, then your towing capacity is frozen at the sticker's weight rating.

The other thing that I've gathered from reading the posts on this site is that the axles are more than capable of handling the highest weight ratings put forth by aforementioned sticker.

Last thing is that the axles are the same for F250 and F350 SRW vehicles. There is a difference in the DRW vehicles (Dana 80 if memory serves). You're looking at major changes and expenses to convert from SRW to DRW, if that's what you're asking.

Let us know what weight you're trying to tow and what type of trailer, i.e. goose neck, fifth wheel or traditional. You are might be capable as it stands, but might want to gear down from a 3.73 to a 4.30 to "feel" a little strong for towing. Or maybe you're looking for more stability.

Be as specific as you can and you'll get some awesome specific answers here. This site is awesome for that type of information.
 
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Old 04-18-2011, 01:17 PM
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Yeah, that's basically correct. If you need the F350 SRW rear axle weight rating, you already have that axle. You just need suspension to support it (spacers, or springs, or air bags). But if you need the dually rear axle weight rating, best go get a new dually truck.

Does your F250 already have the outboard auxilliary springs? Those were optional on '06 F250 but standard on F350.

What is your GVWR? 10,000 is the highest.
 
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Old 04-18-2011, 04:16 PM
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If I'm not mistaken, the tow ratings are pretty close to the same for 350 SRW and DRW.

Are you just looking at the different tow ratings based on gears? You can change the ring and pinion in your current axle from 3.73 to the deeper gears and the truck will have those capabilities.

But as others mention, changing the truck's capabilities does not change its "legal" tow ratings. Many folks do violate the legal ratings on a regular basis, but I encourage you to know the possible risk to do so in your neck of the woods. Every state is different.
 
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Old 04-18-2011, 05:26 PM
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An alternative is to re-register your truck for a high GVW. I have mine at 12K.
 
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Old 04-18-2011, 05:54 PM
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Floridatex, here's a thread that may help convince you of the SD's capabilities. https://www.ford-trucks.com/forums/1...n-the-bed.html
Believe me, I'm not advocating overloading, but like somebody else mentioned, there are thousands of 250's towing over weight every day.
By the way, welcome to the site, it's a great one.
 
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Old 04-19-2011, 06:57 AM
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I have a fifth wheel RV that I am pulling. The chart that I saw when I purchased the RV said that my total gross was 23500 (trailer and truck). My RV has a dry weight of 13??? lbs. It can handle upto 18000 which will put me over the total gross. 250 and 350 SRW weight limits are the same. Dually is more. I have also air bags on this truck. I am not worried about the trailer/bumper towing. I am worried about 5th wheel. I also bought a Contrex controller from Superchips to improve milage while towing. These are the only performance mods that I have made. I just want to make sure that I don't tear up anything while towing. Also the current 2011 f350 Dually comes with 3.73 ratio for towing. The 450 comes with the 4.10.
 
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Old 04-19-2011, 07:48 AM
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Technically, you can't change the tow rating/capacity of your truck. As was stated above, what's on the sticker is what it is. All you can do is make the towing easier for you by changing the gears, suspension, etc. It still does not change the tow rating or capacity. If you're over, you're over. But you can feel better about towing with the new gears, suspension, etc.
 
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Old 04-19-2011, 10:17 AM
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The tow rating is not on the sticker, not sure where that came from. Payload/axle ratings are on the sticker. On my 2010 F250 4X4 SC 5.4L the tow rating is 9,500lbs with the 3.73 axle and 11,500lbs with the 4.10 axle. That is all the OP is asking, and the answer is yes, the tow rating of the same truck is increased with a gear change. GCWR increases correspondingly from 16K to 18K just by going from 3.73 to 4.10.
 
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Old 04-19-2011, 06:57 PM
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This is always misinterpeted GVWR is Gross Vehicle Wiehgt Rating meaning solely the truck without trailer. This rating would be if you had a slide in camper. GCWR is Gross Combonation Wieght Rating truck trailer and load. For example a semi truck(tractor only) may have a GVWR of 52000 on three axles but the GCWR is 80000 on 5 axles. Same aplies to pickups. The combination is in the owners manual based on the equipment you have but is probably atleast 18000lbs.
 
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Old 04-19-2011, 07:01 PM
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Originally Posted by fuelman
This is always misinterpeted GVWR is Gross Vehicle Wiehgt Rating meaning solely the truck without trailer.
Not so, and not misinterpreting. If you have a gooseneck or fiver, GVWR is THE most important spec that you will run into. Ford suggests GCWR that are often very difficult to reach without exceeding GVWR on an F250 Crewcab.

The OP didn't specify, but when he questions his axle rating, and how to increase it, I read that as needing more pin weight capacity.
 
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Old 04-20-2011, 07:47 AM
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My trailer is rated for 18000 fully loaded. A GCWR I found was 23500 for a 5th wheel. The last ime I weighed the complete rig, it was 22950. That weight included full water and holding tanks. It did not however include the 1900 lbs of toys (jetski, quad, M/C) that I take on certain trips. I will be weighing the total rig again the next weekend. I really don't think I would be pulled over to be weighed (but you never know). My concern is to not destroy my truck or make an unsafe situation. AS what has been noted earlier, the tag on the door does not show the GCWR. It only has the GVWR. I did look at the post about driving with 4000 in the bed. But I drive several hundred miles with my RV. That is much different than 20 miles home twice a year.

My real question is what is really different between a SRW and a DRW truck?
 
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Old 04-20-2011, 09:20 AM
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Originally Posted by Floridatex
My real question is what is really different between a SRW and a DRW truck?
There is little difference between F250 and F350 SRW. But a world of difference between those and an F350 dually. The dually has a heavier axle (Dana 80), different springs, different brakes, different wheels.

That is a huge fiver. In my opinion you seriously need a dually. With the toys loaded you might even need an F450. Forget trying to turn your F250 into a safe rig for that trailer.

You are right to ignore that 4,000# thread. That boy ain't right!
 
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Old 08-01-2013, 12:51 PM
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Sharing Cost of Gear Change

Newbie here replying to an old thread Google pointed me to....I've been researching gearing and GVWR/tow capacity for a while and wanted to share cost of the dealer gear change for those that might be considering.

I've recently upgraded to a larger fifth wheel, and while my truck (2011 F250 4x4 crew, long box) could certainly handle it competently and safely before (I will avoid the legality/insurance arguments and leave that to others), I decided to go from the stock 3.55 to 3.73 gears per my dealer service rep and others' guidance. Wanted the dealer to do it since I'm still in warranty.

Just yesterday, they completed the gear swap to 3.73. Total cost was $3,000. $900 in parts, $2100 in labor, roughly. Keep in mind they had to change both front AND rear gears because of the 4x4, so the cost is higher. Thats a big chunk, but worth it for my confidence, power and control when i need it on hills, and a bit more peace of mind.

As you all know, this doesn't change any ratings on the TV, particularly GVWR or RAWR of the TV. Don't think that legally changes the GCWR either, but for some reason that's not published on my door tag - the dealer seemed surprised about that not being on the tag and gave me a big 'good for you' thumbs-up.

And since its a hot topic of contention on these forums, I'll point out that I'm over the TV GVWR by 500lbs on my first weigh-in, just over F250/3.55 tow capacity with the trailer, well under GCWR (ok, so I'm using the rating on the 3.73 gears...just over using 3.55 rating), and just under TV's RAWR - Given my setup and known numbers, if there's a single set of ratings I'm most cautious about, for my dollar it's the RAWR, rim, and tire ratings. I plan to re-weigh after changing the weight distribution of my trailer contents. I've weighed at a local North American moving company's public scale (not CAT) scale. My next weight will be taken at a CAT scale, hopefully I can get that 500 lbs off by moving a quad or two back just a bit, being mindful of pin weight at the same time.

Legalities aside, working through this with the dealer service techs, they know my setup and say (off the record) the truck will competently and safely handle my load just fine....to which I'll add, as long as Murphy doesn't rear his ugly head - which is always a risk you assume even if some do say there's an overweight buffer the LEO or others might grace you with.

Hopefully that helps someone like me who's been lurking for a while doing their research.
 
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Old 08-01-2013, 02:57 PM
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3.73 rear end

I also have a 2011 4x4 crew with 3.73 gearing. I added airbags on the rear to prevent squat when my 5th wheel is hitched. It helped a lot. No more issues with shudder and no issues with warranty.
 


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