E450 Cube Van 4.10 to 3.55 diff

[chase383]

Hi all, first time poster here.
I have sifted through some differential threads here but I couldn't find one that answers my question(s) so I thought I would start a thread. If there is a thread similar, please point me in that direction..
I have a 2000 E450 16 foot cube van that I use for long haul highway runs about 98% of the time. I know this vehicle is rated for roughly 14,000 lbs but I would say the absolute max weight I would have in the truck is 5000lbs.
The truck is bone stock with a DP tuner 60hp econo tune.
My question is, has anyone swapped the stock 4.10 diff to a 3.73 or even a 3.55? I find for 65-70mph cruising the engines revs quite high even though the truck has overdrive. At 70mph it is around 2350-2400.
If you have swapped the diff, have the results been good for MPG and noise level?
Also did you have to reprogram for shift points or anything else?
Lastly, do you feel like it was worth the expense?
Thanks

[Xphobe]

I have a 4.10 rear and when I replaced my rear tires from 30.5" to 31.5" I gained about 1-1.5 mpg on the highway and about a .5mpg gain in the city. With your truck "underloaded" you will probably pick up 2-4 mpg on the highway with no ill effects if you drop a size on your differential.

I do not believe the shift parameters are based off of what the abs reads either, so your shifting should ok, but you might need to have your speedometer adjusted.

If it were me, I would only do it if the amount I would pay to have the rear changed pay me back in 3 years or less. If you know how to change it yourself, even better.

[chase383]

Thanks for the response Xphobe. If I were able to get 2-4 mpg increase I would be very happy. It would easily make the swap worth while. I am having the job quoted in a couple of days..i will see what the shop says.

[lovethydiesel]

Any word on how much it cost? Did you get it done yet? Results?

[sanman28]

I got a labor quote to re-ring and pinion my 4x4 for $650. The parts, including bearings and shims, comes to 1200-1450....depending on OEM ford parts or aftermarket, with Ford being more $.

[chase383]

I had it quoted and it is roughly the same amount as what sanman28 said.
Their are a couple of options to bring the price down.
Option 1. install a used axle with the ratio that you want.
Option 2. Go with an "offshore" gear manufacturer.

I think if I decide to go forward I will use original DANA equipment. The tech I spoke with thought this was the best route because of the quality of the parts.
I wanted to have this done by now, but I had a surprise repair to make (main seal) which had to be done first.