Hi guys and gals! I'm new here and have a question that I haven't been able to get a definitive answer to. I will freely admit I am nowhere near as knowledgeable as many of you who post here so forgive my lack of expertise.

I just bought a 2009 F-250 Super Duty 4X4 Crew Cab long box with a 330 c.i. (5.4) modular in it. It has the Torqueshift transmission with the 3.73 limited slip rear gear ratio. The rear end is a Dana 80 according to the shape of the rear end housing. The front is a Dana 60.

It has about 31,000 miles on it and still has some warranty pending.

I got this unit bought really worth the money. I will use this unit almost exclusively for towing a 5th wheel camper (9000 lbs.), a goose neck implement trailer and grain wagons since I am a grain farmer located in the corn belt. This truck will receive very few miles running without towing a trailer of some kind. That being what it is this truck will still get just in the neighborhood of 2000 miles a year since I have a little Ranger that I use to chase parts and use as a daily driver given the fuel mileage of the heavy duty trucks.

My wife and I recently pulled the camper on a 450 mile round trip and we love this truck. I cannot afford, nor can I justify a diesel or the V-10 so the obligatory "ya' shoulda' got a diesel or a V-10" is not relevant. I could never get into either one of those options for anywhere near what I have in the unit I bought, plus this truck will pretty much do everything I want now but since I bought it right I feel I can throw some money at it because I intend to keep it for the foreseeable future.

OK, we got the background out of the way, here's my question. Since it has the 3.73 gears it wants to do some shifting in the hills and in a headwind. It is rare that it shifts down more than twice. I am not concerned with empty running fuel mileage but I think it might do a little better with a 4.30 gear ratio. Plus it would be very close to the sweet spot regarding RPM while on the road pulling the 5th wheel which would mean less shifting.

I have discussed going to a 4.30 with two Ford truck dealers. Either one can tell me if the stock on board computer can be programmed so that the engine, and more importantly the transmission, will be compatible with a gear ratio that is lower than was available in the 2009 F-250 SD with this engine and transmission combination. As I said before I have some leeway and I am willing to spend some money on this truck but whether the computer will allow the shift points, etc., to be programmed to match a 4.30 ratio is a question I have to know the answer to beyond a shadow of a doubt prior to installing the 4.30 ring and pinion in the front and rear differentials.

The 4.10 was the lowest ratio available with this combination but there isn't enough difference to get to where I want to be as to be worth while to change out he 3.73 for the 4.10. If the 4.10 is my only viable option I will leave it alone and use it as it is and as I said before, that would be OK.

I gotta' believe there is someone out there that has done, or thought about doing, what I'm wanting to do here.

I do not wish to start the whole diesel vs. gas or the V-10 vs. 330 controversy all over again, it's been hashed out many times before. I just need to know if what I want to do is possible.

Thanks a bunch to all in advance.

 

Check this thread out too...

https://www.ford-trucks.com/forums/1...und-truck.html

SuperDutyScaler has the 4.30 gears although his truck is older than yours. It's been done before but I cannot answer about the computer reprogram as I'm not sure. Instead of talking to just a ford dealer maybe talk to a reputable Off Road or Drivetrain shop too. They should be able to explain more what is involved with the swap. Gears are your best bet for pulling and I'd be paying the best shop to do it as I wouldnt want it messed up. Just do the front and rear if you have a 4x4..........but Im sure you knew that.






Oh yea just get a V10

 

You have a 10.5" rear axle, not a D80. Never been an F250 with a D80, that's the dually rear axle.


The truck can handle 4.30s. Been a while since I did homework on regearing, but IIRC on the trucks there's a VSS in the rear differential, so the truck can do the math on the difference between the output shaft sensor in the trans and the vss sensor in rear diff. But that might be the old 4R100 that has a sensor in the trans, I can't remember.

 

Since the truck will practically be a dedicated tow vehicle you may want to consider a set of 4.56 gears. (with stock size tires) The shift points and etc can be adjusted with a custom tune. The speedo gets the signal from the tone ring on the rear diff so the gears will not screw with the speedo. A tow tune from 5 Star would help quite a bit in the towing dept also plus take care of your shift point concerns.

 

The service manager and I took about an hour with the shop manuals and using the vin number among other things and it narrowed down to 2 possible rear axles. The shop manual specifically noted and used the shape of the differential as the determination as to what rear end was under this truck and we both came to the conclusion that given the identifying procedure provided in the manual that it was a Dana 80.

This was the first time I had ever attempted to identify a specific truck rear end and the manual was explicit in it's explanation as to how to identify what it was. All I know is what I read and looked at and I reckon we could be wrong but it sure appeared to be the Dana 80.

 

The D80 is the rear axle for the DRW F-350 trucks. The F-250 is only available in SRW configuration so you get the Sterling 10.5" by default. if the truck does actually have a D80 in it someone probably put it in at a later date.

 

We looked into that dkf. Problem is the ring and pinion was not available, at least not through Ford, for this model truck or this rear end.

We thought if the 4.56 was too low we could always adjust somewhat with tire size. But for whatever reason the 4.56 was not shown to be available. The lowest gear ratio was the 4.30. Now, that having been said, I am far from knowledgeable on this deal and I'm not sure the service manager knows as much as I was hoping he would so it may well be available but it wasn't shown to be the case with Ford. At least not through Ford.

 

That is because you were looking through the Ford parts catalog at the dealer and Ford branded gears. Gears are available for the D60 and Sterling 10.5 down to 5.38. They are all aftermarket gears from companies like Yukon and several others.

Post a picture of your rear diff cover, we can tell you what you have.

 

I will take your word on it not being a Dana 80 dfk. As I said, I'm completely clueless and I'm not sure the SM was all that up to snuff on what we were looking at, either.

One thing I do know is that the rear end was never changed from the time the unit arrived at the dealer for customer pick up when it was brand new.

 

OK, I'll go out and get a pic right now.

 

Count the bolts in the differential cover, a 10.5" has 12, a D80 should have 10.

D80:


10.5":


Here's a good chunk of available gear ratios, down to 5.38:
1999-2008 Super Duty/excursion - 10.5" Rear Axle - 10.5" Gears

At this point I'd forget the dealer and go to a dedicated driveline shop. Google Randy's Ring and Pinion for an example of a great place.
http://www.ringpinion.com/

 

texastech beat me to it but a post the pic anyway.

Sterling 10.5 rear on an 08' 5.4l SD.

 

I'm sorry guys, I can't seem to figure out how to post a picture. I went out and took a couple of the rear end and I put them in the puter but that's as far as I got.

It appears that you guys are absolutely correct. It looks to be a Sterling 10.5. I'mm 99.9% sure.

 

At this point I'd advise you to call Randy's Ring and Pinion, and find a local shop to do the installation. They can probably answer every question you have because gears is what they do, all day every day, and they have an awesome reputation.

 

I upload to the pics to my photobucket account (free) and copy and paste the img code from photobucket into the reply in the thread to post pics.

Image hosting, free photo sharing & video sharing at Photobucket

The dealer can install the new gears but a local driveline shop that installs gears all the time can probably do it cheaper.