4x4 swap, rear axle difference

[UslAura1]

Hello y’all, i have a F250 2wd, with a 10.25 sterling axle with the « C5 » code on the door

And i plan on putting a front axle, transfercase etc on mine from another truck with the axle code « 39 », looks like a 10.25 too. Just asking what is the difference, and do i need to swap the rear axle too??

 

[IDIBRONCO]

With me not being much of an expert on axles, my guess is that the two trucks have different gear ratios in their 10.25s. If that's the case, you'll either have to swap the entire rear ends or swap out the gears.

 

[Nero]

As long as the gear ratio is the same, they are 100% the same. The axle currently under my old mans crew cab 4x4 is out of my old 2x4 pickup. No mods were needed, plug n play.

 

[UslAura1]

Yeah that’s the thing i’m not sure of, i’m wondering if they’re the same gear ratio or not

 

[Nero]

Yeah that’s the thing i’m not sure of, i’m wondering if they’re the same gear ratio or not

Look at the axle tag, should be on one of the diff cover bolts. It'll decode to the axle ratio and if its limited slip or open.

 

[Black dawg]

Will need the lift block from the 4x4 truck as well

 

[UslAura1]

Alright i’ll look tomorrow, also i’ve seen some people buy new brackets for the from leaf springs, but i assume i can just re-use the ones from the donor truck?

 

[IDIBRONCO]

You could try looking up the axle code online. You can usually find out the gear ratios that way too.

 

[KansasIDI]

C5 = 4.10 Limited Slip 6250 lb capacity
39 = 3.55 Open 6250 lb capacity

Same axle shafts, hub, brake components and suspension, different diff carrier and ring and pinion. Make sure they are the same length pinion, the axle code doesn’t tell that. 92 and older is short pinion, 92.5 and newer is long pinion.

 

[u2slow]

The 1/4" difference in pinion/yoke length can usually be absorbed by the driveshaft slip joint.

 

[Nero]

To put it in perspective, I also put a 2x4 dually axle under my 4x4 truck, mine is a short pinion. Original axle was also a shorty so no driveline length change.

 

[UslAura1]

So is there a gear kit i can buy to change the front 3.55 and put a 4.10 in or i’ll have to change the whole diff?

 

[u2slow]

Yes, front and rear axles are re-geared all the time.

Shops usually charge a lot for this service. It can be done on your own.... if you are patient and not afraid to buy tools.

 

[WrenchWhore]

I had a smiliar issue when I swapped out my rear 10.25" that was in an accident. The rear had 1" of tow in. I found another 10.25" axle with long pinion 4:10s with limited slip (came out of a 93). I had the short pinion 3:55's with open diff in the bent axle. I ended up swapping over the 3:55's and yoke from my old axle and used everything else from the new axle. What transmission and tire size are you going to be running?

 

[UslAura1]

Do you know some gear and pinion kit i can buy that’s good for heavy towing, i run 34 inches tires with a e4od trans. But i tow sometimes up to 14 000pounds, already towed a 18 000 tractor too