I'll admit to rushing into buying the truck. It was a great price, not to mention the unique custom additions that were perfect for my needs, Sleeper cab, huge aux tanks, flatbed. I thought it would be a somewhat minor thing to have the rear end swapped for a lower ratio. Ha ha never as easy as u plan! I'm fairly sure a 4:10 ratio would work fine for what i am needing, leaving me plenty of power to pull.Especially with the turbo i plan on adding soon after. Any chance a slightly smaller axle would bolt in place of the 80? I know i could order a ring and pinion that would work, but was really hoping to find an axle i could simply swap that was (numerically) lower than a 4:63, but higher than a 3:73?? Is this an impossibillity?

 

I think a Dana 70 or Sterling with 4.10 gear should be darn close to bolt in, just make sure it is the right width for your rear dually. The leaf spring pads should be at the same spacing. There might be U-joint size issues, either get a conversion U-joint with different sizes on the two axes, or put a new yoke on your driveshaft to match the rearend. The HD has the parking brake on the trans rather than at the wheels I think? If so just leave that as it is and don't hook up the Dana/Sterling parking brake cables, you can remove them and the hardware. Just take your critical measurements and then go to the junkyard and see what you find and could work.

You can get a poor-man OD benefit by going to a taller tire. It will be only 5% or so, but that makes some difference for just using larger diam tire.

 

A Sterling 10.25 out of an F350 Cab & Chassis truck would probably be your best bet.
You need one from a Cab & Chassis truck as the frame width narrows 3" behind the cab, where the pickup frames do not...
If you change axles, though, you'll run into 10-lug vs. 8-lug wheels. I also wouldn't want to give up the rear disk brakes...

 

im not sure if DOT might have a field day with ya running the lighter 8 lug sterling on the F-super duty.might want to check into that before jumping into anything.
it completely lowers the trucks weight rating of course,(and gearing higher reduces combined gross of course,but they can't see that at least) so it could be a massive red flag to them,or it could be nothing if they don't see you with a real f450 load.i dunno.sounds risky.making a phone call sure doesn't hurt first.the last thing you want is a massive fine which could be more than just having payed for another ring/pinion installed lol.
if you find it's ok,or dare risk it.i would guess the sterling with 4.10's you'd need to find would be from the f350 C&C probably then continue on with 38FORD460's advice (sorry had to change your name.just can't say that dirty word or engine LOL!!! )
this is why adding a GV to the f450 is the ticket.and id never buy one without planning this into the purchase.but it's not like those are cheap.i guess its why i have an f250 hey?

DOH,phy beat me to it.

 

Thanks for all the info and advice everyone! I would love to put in a G.V in this truck, it would be a perfect solution, but like u said they are crazy expensive and i've never seen a used one for sale. I'm gonna start measuring and looking for a sterling. As for the D.O.T i've never heard of anyone getting stopped by them here in the mtn west. I'll have to take my chances i guess. I do travel cross country occasionally, but i think it would take a smarter govt employee to spot something like that than i've ever come across or heard of! ha ha

 

DOT won't mess with you unless you are over 26K lbs and running commercial.

With that being said, I think you would be better off with a gear change rather than finding a pretty rare axle in a wrecking yard (4.10 geared 10 lug). Even if you find one, there's no telling that it isn't worn out. Especially considering what most do with a Super Duty truck. You might end up paying twice.

A Dana 80 has 10 cover bolts.
A 10.25 has 12 cover bolts.
An 80 cover is really narrow from side to side. A 10.25 is more rounded.

Jason

 

If it were me, I'd regear the D80. But if you're set on finding a Sterling, are you close to Colo.? If so, I have a 4.10 dually Cab & Chassis Sterling 10.25...

 

I would personally go with a double overdrive system so I could keep the low gears for heavy loads and have DOD for medium to light highway loads. It's not exactly a cheap upgrade but it gives you the best of both worlds.

 

The most common gear ratios in the Dana 80 are 3.54, 3.73, 4.10, 4.30, 4.63 & 5.13. The 3.73 and numerically lower gears use one ring carrier and the 4.10 and numerically higher ratios use a different ring gear carrier. You also have to pay attention to axle spline count if swapping an entire differential unit.
I just bought a Spicer 7231D "Brownie" (2.14 UD, DD and .86 OD) at a wrecking yard for $250 with the shifter and mounting brackets included.

 

Called up drivetrain.com and got some info. Said they have 4:10 that would fit, but i need to call back with the axle code because apparently their are 3 different sizes of carrier? Looks like it will cost around $500 for the hardware and i think i can get it installed for around $300. More expensive than i'd like, but it always is isn't it. ha ha I also asked about their overdrive units, but like i thought they are prohibitively expensive, $3200! I'm still feeling alright about the project as a whole however because i was able to pick up a turbo for my truck for way less than i expected. Can't remember who posted the link on here for it, but thank you! Excited to get these mods put on!

 

btt for this old thread.

How did the gear swap turn out?

I'm buying a '93 Super Duty. 7.3 IDI, ZF5, Dana 80 with 4.56 gears. I'm going to pull the box body off and install a 14' flatbed for local hauling. The 5.13s are insane. Found a wide variety of gears available. I'll probably go with the 4.36 gears.

 

da man:
Last Activity: 04-29-2012 12:19 AM

 

more info for those searching.the gear ratio options offered in the 87-97 F-super duty (f450) which all sport dana 80's are as follows:

axle code 72 = 4.63
axle code 73 = 5.13

and recently i saw a '97 on ebay with a door jam sticker showing axle code G which = 4.30 LS
don't get too excited.iv only seen that one posted so far.
they're not good for just driving around like a pickup (shoot,pickups driving around empty with normal gearing is kinda becoming a thing of the past now due to fuel prices) but they will haul a mean load and can tow heavy equip all day without effort.the brakes are incredible as well.well matched with the massive calipers/4 wheel disc brakes and hydroboost system.
awesome rigs! it is too bad they went a little bit far with the gearing options though.4.30-4.56 would have sufficed.i wouldn't go with 4.10 in mine.you still want to load up/tow and be able to climb hills nicely.you can legally get just the truck to 15k.mines got a custom stretch a bit,and tips the scales over 10k empty.most,if not all will be heavy due to being outfitted with dumps/cranes/welder/generator setups etc.
my suggestion; not a pickup truck.if you see one for cheap but have no need for it,leave it for someone else.