4.10 to 3.08

[rednecksoldier86]

my 3.0L 2003 ford ranger has an 8.8 rearend with 4.10 gears and i want switch it to 3.08. it is a five speed and i drive it constantly down the interstate. has 255/60/15 for tire size. jus needing to know how this is gonna affect the performance/gas mileage for interstate/intown driving before i do the switch.

 

[Earl43P]

Gonna be a dog.

You are running a 27" tire.
I'm 4wd and running a 29" tire (235/75/15).
I was happily impressed with how much peppier mine accelerates with those. Yours must run like a scalded dog. I hardly ever use 1st gear to pull out with these smaller tires (stock 245/75/16's were heavier and 30.4" tall). My effective ratio is 4.33.

You might be happier with 3.73s and they are very common. Personally, since you already have 15" wheels, I'd recommend a taller tire.

FWIW, I get ~340 miles to a tank. I usually end up putting 18 gallons in it when I fill up. I can get more miles out of it if I baby it, but most of my driving is city/rural, literally 35-50 mph most of the time. There's always quite a distance back to the following car if I am first leaving a light. I run 2nd gear up to over 4300 rpm and drop it into 5th and decelerate to the speed limit + 6 or 7.

How are you going to deal with the speedometer error?

http://www.dakota-truck.net/TIRECALC/tirecalc.html is a pretty good calculator.
Run some numbers if you are deadset on keeping that size tire and changing the rear ratio. Ford put 4.10s in there for a good reason.

What was your original stock size tire?

 

[rednecksoldier86]

im still tryin to figure out how to change and who would have the equipment for my speedo change. it is a 2wd truck and the stock tire size 235/75/15. i had 31 10.5 15's for a while when i was helping on the farm. it would run fine down the interstate. but since i went with the 27" tire doing 75mph down the interstate runs the rpms at about 3300 alil too high for me. i drive about 100 miles round trip and tryin everything i can to try to get better gas mileage but worried about how it will affect the rest of the truck

 

[Hahnsb2]

The absolute highest you should go is 3.73, your truck would be a joke with 3.08s, mileage and power wise.

 

[Ozwynn]

yeah ....... 3.73 is a good gear for that engine. 3.08 would suck more gas than your 4.10's. personally I would keep the 4.10's

 

[Mac]

Just looking at the HP for the 2000 Ranger for the 3.0. It's rated at 150HP at 4750 rpm. Going to the 3.08 gears might drop you down to 75 HP assuming a straight power curve. At 75 mph, the wind is a big enemy. You may not even be able to have enough power to get into fifth. Do like they have said and go to at the highest a 3.55 but I'd sure go for the 3.73 gears, or change tire size.
Dave

 

[Will]

im still tryin to figure out how to change and who would have the equipment for my speedo change. it is a 2wd truck and the stock tire size 235/75/15. i had 31 10.5 15's for a while when i was helping on the farm. it would run fine down the interstate. but since i went with the 27" tire doing 75mph down the interstate runs the rpms at about 3300 alil too high for me. i drive about 100 miles round trip and tryin everything i can to try to get better gas mileage but worried about how it will affect the rest of the truck

I get 3,000rpm for 75mph when I put your truck into my spreadsheet. Stock it would have been 2,800rpm to run 75mph. Right now your speedo should be showing 80mph when you are going 75 and your tach should be at 3000, if I haven't confused myself too much here.

Going to 3.08s can't be cost effective. Slowing down would be, though it's tough on that long drive. I'd put the 235s back on as a second choice. I wouldn't change out the rear axle. 3,000rpm won't hurt that motor and the small difference slowing the motor down could make won't ever pay for itself.

 

[rednecksoldier86]

i had put the smaller tires on to discourage me from goin off road with it again. it has done everything i could dream of and more and is still running.

 

[AllanD]

I consider telling you how, but only after you make it abundantly
clear that you understand that what you want to do is a TERRIBLE idea..
And I will do my best to convince you of that...

your truck WILL get massively worse mileage.
You will likely kill your clutch AND your engine.

3.0's get shit for mileage below 3000rpm.

The 3.0 was DESIGNED for a ford taurus running 25" tires
and a 3.94:1 axle ratio...

I've crossed entire states in a Taurus with the tach never
dipping below 4000rpm...

 

[scrapper]

I have a 94 ranger with 4.10 gears and get about 19 miles to the gallon. I had 3.08 gears and got 23 miles to the gallon would not get out of its own way. I am much happier with 4.10's power across the board and I can tow I only have a 2.3 5 speed, not suppose to use for towing with 3.08 gears. When I pull a 5x8 trailer can't tell its there. I thought the trailer fell off after I got the gears changed and went deer hunting with it. With 308 gears felt like I was towing a mack truck. If you really need better gas mileage you may want to check around and see what else you can do? Good Luck either way.

 

[Destroyer000]

iam running a 4 liter in my splash with 3.73s and 255/45/17 tires an i get about 14 mpg out of it.. its sad when it gets the same mileage as my lifted truck with 4.10s an 33s

 

[Green__machine]

anybody know how much of a diffference it would be from running 3.73's to running 3.55, being lifted,33's with a 4L

 

[Sasquatch_Ryda]

With 33's and a 4.0L you would want 4.56's.

Please start your own thread next time you have a question instead of posting it in someone else's thread.