Re-gear and Locker

[CDACamper]

I am planning to re-gear this fall and possibly add a locker to the rear diff. I think I have settled on the Eaton E-Locker but I am trying to decide between 4.10, 4.30 or 4.56 (I currently have 3.55).

I have read lots of posts here and on other forms. I'm hoping to get feedback from someone with a similar setup.

E-350 EB50, Quigly 4x4, Penthouse
Engine: 6.8 V10 (stock)
Axles: Full floating Dana 60 rear and Dana 60 front with 3.55's
Tires: 305 70 16 BFG KO2
Gross Weight fully loaded: 10,600 lbs.

I occasionally tow a trailer with dirtbikes and ATV's with a max weight of 3000 lbs.

I have calculated my effective gear ratio with the tires I have and my existing 3.55 gears. The effective gear ratio is 3.30. I would need 3.82 gears to bring the van back to the stock gearing.

Currently, the van is pretty sluggish going over mountain passes. On the steeper and longer passes, I have to drop down to 2nd gear and my max speed is 40 to 45 at 3100 to 3400 RPM. I also lose speed going up very mild grades even with overdrive off.

Will 4.10's be enough or should I go with 4.56. I could also split the difference and go with 4.30. I am out west so there is a mix of mountain passes and also long stretches of highway so being able to cruise at a reasonable RPM at 70 MPH is necessary.

If you have regeared, I would appreciate your feedback!!

[carringb]

4.56 for sure with those tires. You’ll probably get better fuel economy than now because you’re geared so tall. 4.30 would be ok but still not perfect for the v10, and it’s weaker. I sheared a pinion tooth off my 4.30 gears and moved to 4.56 after that.

[deserteagle56]

I went to 4.56 on the advice of a reputable 4x4 shop. That was 13 years ago and I have never regretted the gearing change at all. Made my van a whole new vehicle. These V-10s love to rev - and higher revs will not hurt them. Used to be the tranny would shift down on every hill. No more. Don't remember just what my rpms are at 70 - somewhere around 2500 I'm thinking.

Thing is, with the stock 3.73 gears and 33" tires I was getting 12 mpg. Now, with the 4.56 gears I'm still getting 12 mpg. The only thing I can attribute that to is that the engine struggles much less with the new gears. (all fuel is logged and mileage is calculated by an Excel spreadsheet, with a correction for the size of the tires)

A side benefit I found with the 4.56 gears - transfer case low range becomes much more useable. Down a steep mountainside, put the transfer case in low range and the tranny in low gear and it becomes nearly as good as a manual tranny as far as engine braking.

[CDACamper]

Thanks for the replies. What is your approximate gross weight when loaded. Are you both in the same ballpark around 10k lbs.?

[carringb]

My empty weight is 8,500. Lightly loaded for a weekend trip 10-11k. Fully loaded weight is up to 25,000 pounds with the trailer.

[CDACamper]

Thanks Carringb. I am rarely north of 13k so that makes me feel better about 4.56. Are you also running 33" tires?

[carringb]

My tires are only 32”

[CDACamper]

A quick update for those looking to regear/add lockers. As it turns out, I have a 32 spline axle in my rear Dana 60 and Eaton does not make their ELocker in that configuration (they have 32 and 35 spline). My front Dana 60 Kingpin is a 35 spline. So my options were to go with an ARB air locker in the rear or go with an Eaton ELocker in the front. I could have changed out the rear axle to 35 spline but that would add a lot of $$$. I could have also gone with a limited slip like the Eaton TruTrack or an auto locker but decided against it for various reasons.

I have opted to go with 4.56 gears and an ARB locker in the rear. I will run the front diff open and have the option to add an ARB locker in the future to the front if I feel it's needed. The 4.56 gears will put me at 2340 RPM at 70 MPH in overdrive, which I think is reasonable for highway cruising. The cost breakdown is: Labor is $1330 and $2520 for the parts

By the way, the Kingpin Dana 60 with high pinion is a very highly sought-after axle . I was unaware that was a thing.

[TheLetterJ]

A pair of custom made 35 spline Dutchman axleshafts would have cost less than the difference between a 35 spline e-locker and your 32 spline ARB... but at least you'll have onboard air now.

[Vanimal]

King Pin front axles are truly the best in weight capacity, wear and repair. There is also several king pin caps made by companies for double sheer heim joint steering that has been the best answer for converted linked front axles in death wobble fixes.