rear axle ratios

[roger Biddlecombe]

I own an 01 Sport trac 4X4 with 4.10 gears,very happy with this trouble free SUV,Question I hear people talk about 3.73 rear ratio,I do no mud plogging & very litle of road ,Just rocky non paved roads each winter in Mexico {made top of 16000ft volcano last winter} Can anybody give me pros & cons of changing to 3.73? Note I am a retired mechanic so would rebuild myself if I consider it worthwhile, Better gas milaege would be nice

 

[Todd Z]

The MPG increase would not be that drastic to do the swap, Unless you can find another 4wd St member that would like to upgrade, then you can swap the rear ends out of both trucks...

You can not simply change the back only because you have 4wd... You have to swap front and rear...

Todd Z

 

[Kevin Palmer]

You will get SLIGHTLY improved mileage with slightly less performance.



Others have done comparisons and the mileage increase is actually pretty small for the amount of the labor. Here is an example that I just pulled from the Mileage log, (here at the site).



Group 1

Type of Miles = Mixed

Automatic Transmission

Tonneau Cover

Four Wheel Drive

3.73 Axle

16.37 MPG



Group 2

Type of Miles = Mixed

Automatic Transmission

Tonneau Cover

Four Wheel Drive

4.10 Axle

15.95 MPG15.95 MPG

 

[Travis Munday]

A 3.73 will give you less low-end torque and pulling power, but better top end and MPG, although the difference isn't that great. You'd probably never even really notice a difference between the two.



Pros: Better MPG (in a perfect world)



Cons: Cost, new gears aren't cheap, even doing the work yourself

Downtime, unless you have another vehicle or are quick at gear swaps

Possibly no difference in the real world



Honestly, 4.10 is the better ratio for offroading, you get more pulling power down low, which could be the difference in pulling over the rocks, or just sitting there wishing you had a winch.

 

[Yardsale]

Acceleration and uphill performance will not be quite as good with the 3.73 (and you will notice).

 

[Andy Szkutak]

ill trade my open 3.73 for your 4.10! thats what ive been lookin for. i just need a way to get it to u and get yours to me lol and i dont know how to put it on or take it off...



if your interested email me [email protected]



thanks

andy

 

[Johnny O]

Changing the front gearset is not for the faint-hearted though. I have 3.73's and 265/75-16 tires, the truck is turning 2200 rpm at 75 mph and I got 20.6 mpg on a recent trip (that's all allowing for a 10% speedo error). 16.8 mpg coming back, which is the subject in another thread. On the other hand, all off-roading is done in low range. Heck, I need low range just to pull my jetski up the hill into my back yard.

At least around here, for two new gearsets plus install I'd be looking at around $700, so like any mod you've got to figure how long until you save that much in gas.

 

[roger Biddlecombe]

Thanks for help ,I will stay with 4.10