Has anyone swapped out a axle with the 8.8 diff housing, for a 9.75. I hear the drive shaft will need to be shorter I have a 2011 scab with a 3.7l. Seems any meaningful boost to payload will require a new stronger rear axle. Looks like towing my RV gets a little bit close to rear axle gawr - rear curb wt. Which might effect how I load it.

 

The axles directly swap, but it still doesn't change the door sticker.

 

I don't care about the door sticker. Besides the axle, bigger springs, would brakes swap over also I hear the pinion area on the diff housing is longer on the 9.75. how tuff would it be to find the driveshaft to fit.

 

I enjoy mechanical swaps as much as the next guy, but the cheaper and easier option is to sell your current truck and buy one that is correctly equipped. They aren't rare. Unless you can get all the parts for free and you want the practice for a learning project or something. Then go ahead.

If you are just occasionally carrying heavy loads at low speeds (like farm work) then a set of airbags would probably take care of you a lot easier than the work you are planning.

 

I didn't want a turbo, so I have a 3.7l they didn't package them together. The axle is only 700$ so I doubt that

 

You have the smallest motor (HP) available in an F150..... Big axles and drive shaft are not going to makeup for no HP.

 

RE: Driveshaft. You will have to have one made. Expect $200+ depending on your design. When you get the 9.75 axle, get the driveshaft with it.

Serving suggestion.

FWIW

 

Axle may be $700, but the rest of the parts will be another $2000 or more. There's zero chance you'll be financially ahead to do this parts swap compared to just changing trucks. Although like I said, if it's enjoyable to you, go nuts, keep receipts and keep us posted. It'll be interesting for sure.

 

I don't need extra hp but I need extra capacity I don't like the idea of running at 90-100% the capacity of the axle. I had a f250 that was way over built for this trailer and had terrible fuel mileage, and used 4 gallons of oil per oil change. the 3.7l v6 has more hp and more gears in the transmission to efficiently transfer power than the 4.6l v8 that Ford placed into f250's years ago. My truck has a tow package so tranny cooler, larger radiator are already in. I wanted a rear locker anyways, I can get a axle with a locker already installed for not much more with springs and a drive shaft I'm thinking 1,500$ tops. Used axle, new springs and drive shaft

 

horse power is torque x speed ........ you have decent HP if your running 6000 RPM......... your problem is going to be low end torque ........ what HP do you have a 2000 - 3000 RPM........... that will be the problem.

 

Then I would suggest you go right ahead sir despite the excellent suggestions that were offered.

Our FTE community is serious about safety and abiding by the law and they aren't going to recommend to you that do something to your truck that will side step Ford's intended payload / tow ratings. No matter how you change your truck's capabilities, the designed ratings will remain the same.

 

Good luck brother. It's a cool idea, and should be a good learning experience. Post pics of your project, because we love that stuff.

 

Many trailer tires are rated for no more than 60mph. Plus I'm not going to drag it through the mountains.
Yes it will be slow, accelerating, and so is a 18 wheeler. I could deal with that the one day a year to two years that I move the trailer.

 

I wasn't really asking for fte to recommend this or that. But if anyone had swapped those axles what parts they needed as it would save me some time. To get it back together. But since you bring it up, I didn't realize this fourm was baby sat by uptight moderators. I guess you never owned a jeep, you'd poop your self knowing on those axles people are commonly cutting and welding on new drag link mounts, and control arm brackets as they lift.
People swap axles all the time on jeeps and its much more painful then what sounds like on the f150, a direct swap without cutting and welding.
Years ago I worked for Toyota, making the tundra and Tacoma, look at the payload on a tundra and a f150 and look at the frames. I'm not trying to do something stupid. I'm looking for 500lbs more of payload I'm not trying to get to the f150's max tow rating. My weakest link is the rear axle, and springs.
I'm sure someone out in the world regularly is overloading there f150 with building supplies if they know it or not which I'm not recommending. Unfortunately by talking about these subjects might make the roads actually safer, and maybe others can learn add a leaf or airbags won't safely solve everything even though it looks like the truck no longer sags. I don't own a truck scale and I prefer not to be so worried about it. I was thinking about a getting a locking differential so its actually not a outrageous cost.

 

I've started looking into a custom drive shaft, so far my first contact can't physically make one to the specs. I guess they did cars mostly as they are limited to 65 inches, and could do the same design.
Once I get some numbers together I'll decide if it's a go. If not I'll be looking for a truck axle scale.