9.5 mpgs for me is really only a .5-1 drop in fuel mileage. Nothing terrible, but noticeable.

SLE, you say your lower gears actually hurt performance? Or it just "feels" slower?

And I loved that write up 3Zs! That's a pretty clever way to do a hub disconnect without popping the hood. Im definitely going to look into that. Its definitely something Id use more than just for a gear swap lol, especially since I own a camper (id prolly end up disconnecting the vacuum hose for the duration of the gear swap anyways, just to be 100% sure someone doesn't put it in 4wd).

Day to day driving feels slow and technically will be unless you turn more RPMs accelerating. You won't notice an increase in performance unless your foot is well into the go pedal or you've got a trailer hooked to the back end. That said if you have 3.73s and you increase tire size I think you'd notice an ill effect on your day to day driving. It seems the 3.73s or 4.10s provided a nice driving experience on a fairly stock truck. Frankly, all the extra torque with 4.56's is wasted in day to day driving without a trailer. If it was my daily driver there's not doubt in my mind that 3.73s or 4.10s would be more comfortable yield a better driving experience. On the flip side I wouldn't live with performance of 3.73 or 4.10 gears towing my latest camper.

My true an honest opinion; if your camper is truly 8,500lb and your towing of it is relatively limited to some recreational use, I wouldn't spend the money. The performance of mine was more than acceptable with 3.73s up to about 10k lbs. If you plan to upgrade campers, tow in mountains, and or this is going to be more of a dedicated tow rig, then gear it and gear it deep!

Another quick question: is the Ford D60 different from the Chevys and Dodges? I looked it up on Wikipedia and they say Ford used reverse cut gears.

Also, do I have to change carriers if I go 4.56s or deeper?

And lastly: since the front end technically doesn't spin until its locked in, would a spool be advised? If I have to change carriers I had might as well at least put a LS in there, maybe even a lunchbox locker

So based on reading the 4 pages....if I want to run 285/75/16 on an Excursion....probably want to go 4.56 gears? This will be a tow beast

Heck Id go ahead and slap on some 4.88s if I were in your shoes. Especially if its mostly a tow vehicle

4.30, 4.56, or 4.88 depending on trailer size, highway speed you like to tow at, RPMs your comfortable turning, and so forth. 4.56 & 4.88s will turn fine at highway speeds of 60 to 70 mph in both 3rd and 4th gears. You may find that if you need second gear, the deep gears will make it turn to many RPMs at anything over 50-60 mph. I have one hill I found myself dropping to second gear on and found I'm limited to about 50-55 mph unless I want to turn more than 4500 RPMs. I had plenty of power to accelerate but ran out of RPMs and third was just a tick to steep. With a 4 speed trans its important to look at you RPMs at a given speed in each gear. Just food for thought. I'm running +-22k lbs through rolling hills and have yet to wish I would have went to 4.88s. For me I think It'd be heading towards the steep side. OD is gonna be pushing 2500 RPMs at 70. 3rd will be well into the low 3,000 rpm range. Bigger tires, absolutely!

Thats the only bad thing i have to say about my 4.30s too.

Yeh, if your running the stock 265 tires, my 4.56s put me just barely a tick deeper gearing wise since I'm running 285s so they should perform close to the same. This is the primary reason I think 4.88s might be heading to the steep side with anything close to a factory tire size, at least with the old 4R100. A couple more trany gears spaced correctly would be awesome!

I think It kinda depends on a lot of other things also. If you live in the hills and hollars and drive the interstate, then gears is a bit of a juggling game. You want a low enough gear to get ya going on a hill but not so low you run out of gears.

For me, I live in the plains and the nearest interstate is an hour away. I can just about choose any gear I need.

If push comes to shove, do like Im planning: go with 4.88s and stay off the interstate

What about 4.30s and 285's?

285 is the width. It depends what the aspect ratio is for the height.

Stock (for my truck) is 275/65R18, so a 285 is pretty well stock. 4.30s would be perfect

285/75/16 is the plan. So i guess either 4.30s or 4.56.

I would assume if I want to go 315/75/16 I would want 4.88s

With your plans to pull up to 12k with a V-10 EX around hilly Central/Western PA I wouldn't spend the money to only go as far as 4.30s, 4.56 would yeild a better towing experience with stock or stock sized tires in my opinion. If this EX is primarily a tow rig and you are looking to run the taller 315/75 tires (approx 35") then I would spend my money on 4.88 gears. With the taller tires your effective ratio will drop back down to around 4.40 to 4.50 or so depending on exact tire specs. When I ran my 35.24" Nittos through a tire/gear calculator I came up with an effective ratio of 4.39.

Hey guys, Iv got a quick question. Iv ordered a switch to do the "Lo Range 2wd" mod. I browsed through the article 3Zs posted to refresh my memory. The guy who did the write up wired the switch into the "hot" side of the ESOF wiring. He then said, wired this way, the switch would have to be on constantly to allow normal operation of the ESOF. He then purchased a relay to allow the switch to work properly.

My question here is: instead of wiring the switch into the hot side of the ESOF, wouldn't the switch work properly if wired into the ground? My theory is, when you click it in 4Lo, the battery sends the signal to the ESOF to engage the hubs. The signal then cannot be grounded since it has to run through the switch before grounding. Flip the switch, it grounds the circuit, and you have 4Lo!

But my theories are usually wrong...

Where was this "mod" posted? Sounds like a good read