Just curious...

[rusty ol ranger]

What roughly would be the MPG difference on a otherwise stock 2.9/5sp/2wd if i swapped the rear for a 3.73 or 4.10 from the factory 3.45?

Only reason im asking is i know a guy who is scrapping a 4 banger 2nd gen and i havent been over to look at it but i assume its atleast a 3.73. He said i could snap it up for almost free...but i dont want more junk laying around if its going to totally kill my mileage.

 

[fastpakr]

At most a couple of percentage points. Do it!

 

[Uncle Gump]

How many plug wires you planning on pulling to control the power with 4.10 gear?

 

[rusty ol ranger]

How many plug wires you planning on pulling to control the power with 4.10 gear?

I could pull 3 and still smoke a 3.0 even with the 3.45!

 

[Uncle Gump]

I could pull 3 and still smoke a 3.0 even with the 3.45!

Yeah... that's exactly the way I feel about my 2.9L too.

But seriously... does your rear end need replacing?

 

[rusty ol ranger]

Yeah... that's exactly the way I feel about my 2.9L too.

But seriously... does your rear end need replacing?

Its leaking out the pinion. Not bad but it may become an issue sooner then later. Other then that it seems pretty solid. This is more of a "its cheap and rear ends are easy to swap" type of thing.

 

[fastpakr]

If you were down this way, I'd hand you a complete 4.10/7.5 axle that's in my way.

 

[Uncle Gump]

I've always liked your optimism rusty...

in all honesty... I think either the 3.73 or a 4.10 would be a perfect fit.

 

[rusty ol ranger]

If you were down this way, I'd hand you a complete 4.10/7.5 axle that's in my way.

I apperciate that man.

I've always liked your optimism rusty...

in all honesty... I think either the 3.73 or a 4.10 would be a perfect fit.

thats kinda how i felt too. Trucks got plenty of oomph as it is but you can always push more.

And that 3 plug comment was total sarcasm....id lose if i yanked 3....id say 2 at most

 

[ericbphoto]

I could pull 3 and still smoke a 3.0 even with the 3.45!

 

[sgtsandman]

My experience with the 1998 Ranger with the 2.5 Lima that came stock with a 3.45 rear end and swapping to a 4.10 rear end was that the gas mileage was the same. The poor, underpowered engine was struggling so bad with the stock gearing that it was burning as much fuel as it would with the 4.10. So I went from 21-22 mpg to 21-22 mpg.

Get up and go was way better and it no longer struggled with hills or maintaining highway speeds less than 70 mph.

 

[racsan]

my ‘94 2.3 2wd longbed came with a 3.45 that I swapped for a 4.10 , did it very soon after getting the truck so I dont know what mpg it was getting. Now it gets about 21 mpg at best but the acceleration is so much better, can pull trailers now which it would of struggled with before. In fact the owners manual states with that engine/rear axle ratio “trailer towing not recommended “. my best 2.3 milage was with 3.73’s, my ‘88 2wd supercab got 29 once, 23-24 on a regular basis. (with stock 14” tires) . With my ‘94 I went right to 15’s after the axle swap, 235/75/15’s work as long as I dont pull the heavy box trailer, the 225/70/15’s do fine for any towing and it will get up to highway speed a bit quicker and seems to be the best size for my engine/gearing.

 

[snoranger]

In my opinion, 3.45 to 3.73 wouldn’t be enough of a difference for the amount of labor. If your doing it because rear is blown, worn out, etc than it’s worth it. But depending on your tire size and average loaded weight, 4:10 may very well be worth it.
My ‘90 4.0l got about 1 MPG better going from 3.08s to 3.73s... the 2.9l makes a little less torque and your gear swap would be a little less drastic, I’d expect about the same MPG and slightly better acceleration with 3.73s.

 

[scotts90ranger]

I doubt you'd see more than a couple tenths of a mpg... my '97 has 4.10's and a 2.3L and I've had 26-29" tires on it and correcting the odometer for changes it didn't do squat for mileage as long as I cruise under 3000rpm which is around 75mph in 5th with the 225 70 15's that are on it now... The 22-24mpg it gets depends more on if I get stopped in stop and go traffic or just get to go through than anything else... a year ago I did a 1800 mile road trip in a weekend all freeway and it got 22mpg just like it did on my commute...

 

[Roert42]

I switched from 3.08s to 3.55s on my f150 300 w/m5od. Picked up 3mpg (from 15 regardless of the situation to 18), and made it much better to drive. Lost some top speed, but I rarely took it over 50mph anyway. I miss that truck.