3:08 gears how common are they?

[Lee]

I'm looking to increase the mpg in my 96 ranger 2wd.

It has the 2.3L with a 5 speed manual & 7 1/2" 3:73 gears.

I'm going to start looking through the junk yards for a 3:08 rearend & it would be helpful to know which years & makes that rearend was common in.

Thanks Lee

 

[Captain Ledd]

Not rare, though not common. I know, vague answer. My friends 2wd '94 4.0L has 3.08 gears in it, I know because I checked the tag.

There's a little misnomer about the 4 bangers though, they like to rev. In fact, when I went to 4.56 in mine with just a 235/75R15 tire, my mileage increased across the board! (by means of 1-2 mpg, I did get a little more out of the tanks) I'm doing 3000 rpm @ 70 mph. Peak torque doesn't come on in the pre '99 engines until about 2800 rpm, peak hp even higher. I often equate a 2.3L 4 cylinder running at 3000 rpm to a 4.6L V8 @ 1500 rpm. Same number of power strokes, but the V8 appears much more economical on the surface. You need a certain amount of torque and horsepower to propel the vehicle down the road at a certain speed, if you're not where the engine can make that power easily, it uses more fuel and burns it less efficiently in a desperate attempt to try and create the power it needs.

So what will make this work is your driving style, how big are your tires? What speeds do you drive? mostly highway or mostly stop/go? Do you do one more than the other? Would you prefer better stop/go mileage or better highway? Do you tow anything or have the truck loaded often?

And you should realize that it IS a pickup afterall, and you're just not going to get a whole lot better than the high 20's or very low 30's (and probably only once and a while at that) with it ever. It just doesn't have the aerodynamics or lack of weight.

 

[Mac]

What the Captain said. You'll be crusing at such a low rpm that you'll have maybe 40hp and it takes about that to move thru the wind. I had a '99' with the 2.5 and 3.45 gears. Great in town but worthless on the interstate at any hill.
Dave

 

[bobbywalter]

cool......


x 10 with these guys.


i replied in his other post....

4.0 trucks had 308 gears......because they could actually use 308 gears.

 

[RonD]

Don't think I agree with all the above.

If you are using OD as a "gear" and expect to pass and accelerate up hills in OD then yes, go with 4.10 or 4.56.
If you want OD as a gas saver then go with the 3.08

'96 2.3l shows 117HP at 4,800rpm, 135ft/lb torque at 2,400rpm

Assuming stock 26" tires
3.73
60MPH
4th gear 1.00 = 2,890 RPMs
5th gear .75 = 2,170 RPMs

3.08
60MPH
4th gear 1.00 = 2,380 RPMs
5th gear .75 = 1,790 RPMs

70MPH
3.73
4th gear 1.00 = 3,350 RPMs
5th gear .75 = 2,530 RPMs

3.08
4th gear 1.00 = 2,790 RPMs
5th gear .75 = 2,090 RPMs

4th gear stays at or just above torque spec with 3.08 at highway speed
And you have the "option" of using OD
While I agree that if you are doing more around town driving the 3.08 wouldn't be the best choice.
The 3.08 just like the 4.56 are specific use choices.
MPG ultimately comes down to the driver

 

[Captain Ledd]

I had 3.73's and 29" tires (the 235/75R15's), and overdrive was useless on the highway, as in almost flooring it. I went all the way to 4.56 because if I was going to drive 70mph in 4th, I might as well gear it to do the same RPM in 5th and get some more low end starting power. No sense in having an extra gear you can't use. High gears only really work if you make enough torque and horsepower down low in the RPM range.

2000 rpm in not enough IMO. But it does come down to the driver and use.

 

[bobbywalter]

you can disagree, but you go ahead and put the vacuum gauge on and run the 4.10 truck, 3.55 rear in the same truck and then the 3.08 rear in the same truck all with the same tires and same drive cycle....then report actual economy.....and see if you still disagree.

maybe that is why 308 gears and 4 whizzer rangers are actually rare past the efi cross over.. could be a simple coincidence i guess.



some of the first years had a smaller 6 7/8 gear rear axle with really tall gears and tiny tires as options and were common......usually a 2 liter carb engine. pretty useless if you want to go 70 mph.....and driving them just really sucked. almost as bad as the non turbo diesel models. pathetic.

a case of playing up to the ratings tests...

308 gears and rangers are somewhat rare overall, but 4.0 trucks hold the majority in my experience. usually 2wd rangers with 4.0 and auto.


that is just the way it is.

hey, the numbers you are using are correct, the manner of application is not. in reality for normal driving that is a small target for this weight and vehicle style. and like you said, individual driver and actual drive cycle needs are pretty key to maximzing any scenario.


if anything you want to be over target at torque peak rpm with a 4 whizzer ime though..


wind resistance and rolling resistance begin to compound loads past 40-50 mph, and those are some low hp and tq numbers to achieve ideal mpg at that load.


your logic would indicate better mpg at lower rpms. often times this is the case with most setups. no one disagrees with that.


depending on tune, my truck usually achieves best mpg between 50-55 mph. its less at 45 mph like 18-19....possibly because the converter is unlocked at that speed.. goes back up at 35 mph. YEAH, i drove it 58 miles at 35 mph to and from to test that several times. but only 20-21 so it did not beat the 50-55 average....i dont have any textbook explanation for that. but its a fair bet to say in a 2wd ranger with 308 gears and 235 tires it would get much better economy all around with the same exact powertrain from my rig transplanted into it.


those aero factors going from my fat bastard truck to a normal 2wd truck also apply from 86 to 2000 body styles to some degree. not 4mpg....but likely .7-1.2...no surprise if it was nearly 1 whole point which is huge at hiway speed.

the control system from the 86 is archaic in comparatives to the 2000 2.5 engine as well. so maximizing it to work with 308 gears may not be so useful and not easy to do.

if you want the 29 mpg the 2000 was able to deliver it will take some serious balance of gearing tire size and tune. tune in this context takes in many details which are biased towards your drive cycle needs and goals.. from the factory they have a certain baselinewhich is a giant compromise and not ideal for every need. and for good reason.

anyway, yours goals of matching the 2000's fuel economy the cost and effort of which would drive my to a diesel swap....solid 30's....and much much more power. look up green geekers build on this forum. its the way these trucks should have came from ford from day 1. his truck outperforms the junk ford shoved down our throats from day 1 in a 2wd general purpose mini truck. it would likely be the best 3-5 k you could spend if you prefer the size of the ranger like i do....i know i dont regret swapping a diesel in....well, i regret not turbo charging it.....easy fix, i have it all in the garage too. but i been driving it like this for 100's of thousands of miles since 2008 so its cant be that big of a regret.

 

[Lee]

Well for the most part I'm using this pickup for commuting to & from work.

Right now I'm driving 300 miles a day 99% highway miles doing anywhere between 55 - 70 mph

This is not the norm but it's what I'm doing for the time being, on average I usually commute about 200 a day & it's not to bad, but with this job site so far away I'm looking at all the options for better mpg.

So it sounds as if 3:08 years might be more headache than their worth, what's the happy medium??

3:56 & a 2.5L engine??

Thanks Lee

 

[bobbywalter]

well.....given that scenario......small 14 in tires and 308 gears could very well be a perfect solution.


i get axles between 75 and 150 for light duty at the yards i shop at....and a decent set tires that 14 inch size off of craigs list 50-100 bux... so realistically i might pull it off for 200 bux and a day or two labor if there was actually a 308 rear at the junkyard in decent shape. and that is one hell of an if.


so if you hit the combo right the first time and can do the work yourself....and say it put your average to 29 from 24.....at 2.60 a gallon for gas after a year or so you would be even money......this is all best case scenario.


in a 2wd ranger....well, i would not own a 2wd ranger where i live....but say i was where i could use one.....for 200 bux a year.......nope....i would not do the work...but i am a lazy bastard like that..

 

[Lee]

Finding the 3:08 is the big if.

I'm spending $225 a week in fuel & bridge tolls, it would pay for itself pretty quick, if I could get it for that price.

 

[alwaysFlOoReD]

Most common - 3.45. Next 3.73. I've run across 3.27 fairly often, 3.08 never...at least in in rbv to 1991.

 

[bobbywalter]

Finding the 3:08 is the big if.

I'm spending $225 a week in fuel & bridge tolls, it would pay for itself pretty quick, if I could get it for that price.

yeah.....costs are relative i guess. i can spend 400 in a day to go to the work area if i have to buy 100% pump fuel.....1500 one way sux....then a 100 or so a day and 1500 back. so 2-3 mpg is huge when you average 50k+ miles per year. its why i drive diesels. or really small cars. one extreme or the other all depends on conditions and what i need to do. but last year was pretty slow...


3-400 to the outside...and the big if is also a big relative to where i am located...in paradise ca they my be breeding like rabbits in the junkyards with buy 1 get 1 free sales....

but if you have the skill putting an axle from a blazer or jeep is an option as well.....the jeep will allow the wheels to stay the same..

 

[Lee]

Thanks for the help guys, I'll be checking out the junk yards looking for a good 2.5L engine & a higher geared read end, hopefully a 3:08 if not then a 3:27.

Like I said this long commute is temporary, I'll either be getting a company truck or quitting my job for one closer to home real soon.

I'll either swap rearends & motors if its cost effective or I'll just pick up a newer Ranger that gets better MPG.

Thank again Lee

 

[RonD]

Assuming 12.5gallons at 24MPG to get 300 miles
Changing it to 29MPG would be 10.3 gallons burned, so saving money on about 2 gallons.
$6 a day, not nothing but it will take awhile.

And a Ranger is just a heavy commuter vehicle, seems like Calif would be full of "less expensive"(high miler) 2 door 4cyl cars that get 32+ MPG.
Putting 300 miles a day on your Ranger just seems like a waste unless it is already a high miler.
Keep the Ranger for weekends and trash the car



Yes, I doubt even Ford could sell a 3.08 with a Lima 4cyl, lol, I am sure there were some made, as requested option, but anyone taking it for a test drive wouldn't be too impressed.

Yes alot more to it than liters of air consumed.
Lima in a, 5,800lb F-150 wouldn't get very good MPG at all, even with 3.08 joking, in the 3,200lb Ranger it was just OK.
In an 1,800lbs Yugo it would get GREAT MPG
Power to weight is important.

I don't think the power(torque) would be an issue with the 3.08, simply because you can go to 4th or even 3rd as needed, for the terrain, OD is just an option available on long flat stretches of road.

Yes a vacuum gauge is actually a good idea, when you want to squeeze the best MPG from an engine a dash mounted vacuum gauge gives you real time info and feedback to keep your foot off the gas pedal.

Happy medium could be going with taller tires.
I just assumed you had stock 26" tires
If you went to 29" tires it would in effect change the axle ratio to 3.34, I don't think that would change MPG much, because the 29" tires are usually wider and weight more.
But don't discount bobbywalters Vacuum gauge idea, they don't cost much and just having that feed back in real time can help you maintain best MPG.

 

[ridgerunner]

My 94 4X4 w/ 4.0 single cab, short box has 3:27 gears FYI. Not that I'm sellin', just tellin'.