New to the Forum... Thank you all for your information. Not sure how this works or if I am posting this question in the correct place but here goes...
I have an 02 excursion with the 7.3..... rear end needs to be reworked and I am thinking of lowering the gears from 3.73 to 4.30 and adding an ARB. I currently run 315 but may go bigger in the near future. I also am adding armor front and back....I pull some but mainly use off road and as a daily driver...
Thoughts?

 

 

I wouldn't recommend an ARB in the rear of a daily driven vehicle, on the street with it unlocked all you have is a $1000 open differential that does nothing to give you better traction when one wheel is on a loose/slick surface, sure you can lock it if you want to wait for the compressor to build pressure and the locker to engage but with it locked you have a $1000 spool that will chirp tires going around the corners. I think you would be better off putting a Detroit locker or Detroit Truetrac in the rear. For gears I would go with 4.10 if you are keeping the 35s and 4.30 if you are going with bigger tires, however if you do get 4.10 gears and decide to get bigger tires later 4.10 gears and 37s isn't bad on a 7.3. The 7.3 makes its torque low in the rpm band and doesn't need to rev as high as a 6.0 or a gas engine.

Gear calculator Gear Ratio Calculator

 

 

pirate4x4_camo
thank you for your thoughts and the link to the calculator... is the change out something I could handle myself or should I have a shop set it up

 

@00t444e
I like detroits and have run them on my jeep but they can cause issues in the snow on the road

 

Need a few speciality tools to R&R the diff and set the pinion debth and backlash but DIY is not unheard of.... I have a gear shop do mine.

Ive run both the Detroit no spin locker and the Tru Trac and prefer the Tru track on the street but the Detroit in the dirt the clunking and banging of the Detroit is irritating on the road. I’ll never run anything but an ARB again. Unless it’s a spool. LoL

 

I have a Detroit in the rear of my truck and a Spartan auto locker in the rear of my Jeep, both do fine in the snow and rain and they don't have any banging, jerking or poping like people always say they do, the new Detroit soft lockers are very tame. If you don't want a full Detroit locker in the rear you may be better of with a Truetrac it is a gear driven limited slip that has no clutches to wear out and it does a much better job transfering torque than the factory limited slip does. You could put a Truetrac in the rear and an ARB in the front.

 

I'm doing it right now - replacing 3.73s with 4.30s.

https://www.ford-trucks.com/forums/1...ion-build.html

The rear will get a Detroit TrueTrac. I'm leaving the front open. I plan on running 35" tires, but I could step up to 37s in the future.

CR

 

On 35's, If you are towing or ever will tow, get 4.88 gears. You'll come close to a stock 4.30 gear with OEM tire size performance.
If you never will tow, get the 4.30 gears. They will be closer to stock performance with those tires.

ARB's are expensive. figure about $1000 per axle for the lockers, Then you have them installed for about 600 to 800 bucks each. It starts to run into ouch time. Then there is the wiring, and, if they are ARB's, installing the compressor and lines. Then where do you put the switches? That is why I ended up installing myself. But you better be very mechanically inclined and have the tools to back it up. ARB's are not nearly as easy in total as a standard Diff to change out.

 

For a gas engine that would be right but for a 7.3 Powerstroke you don't want gears that low unless you have even larger tires. The 7.3 has a lower rpm range and makes peak torque at a much lower rpm than the 5.4 or 6.8 gas engine.

 

 

Yeah. That was a mistake. I'm thinking gasser.

 

I did the 4.10’s with a trutrac last year on my 7.3 running 35’s. Honestly didn’t notice much difference,which is ok as I mainly did it in preparation for the travel trailer we plan on getting next year. If everything goes well...should also be getting a BTS trans before we get the trailer.

Ford did the work with OEM rear 4.10’s and Yukon up front with the newer aluminum rear diff cover for $2k

 

Thank you all for the info and opinions....I decided to go with the ARB in the rear and 4.30's... I am having my mechanic do it ( I wish I had the time ) and it should be done by the middle of next week... due to a shload of little things on the front end that needed some attention it is going to hurt the wallet......I will keep you all posted.