Results of dropping from 4.10 to 3.73 gears?

[Tribefan]

I was wondering, if I were to have the gears in my Ranger changed from 4.10's to 3.73's, would it even be worth it in regards to helping my MPG's and engine noise due to the lower RPM's? If I'm at 2500 RPM while cruising at 70 MPH, any idea what they'd drop to with 3.73's?

For the record, I'm not whining about life with my truck. I'm just wondering if this would be something worth doing to allow me to enjoy it even more.

 

[80351]

I was going to tell you I'll go out and run mine down the road but for one you didn't say what size tires you have and 2 I don't think I can get up to 70.
I could tell you at 50 but again you didn't say what size tires you have and seeing as I am running 31's unless that is you are roo
Dave

 

[mkpecor]

and what motor?

 

[Kona]

It wont make to much diff , mine has 235/75/15 's right now (babies winter booties.. Latitude Ice-X's ) with 3.73 gears and think I run almost the same rpm at that speed on the flat. Don't recall really looking at the tach but my Flowmaster 40 series makes such a nice sound @ rpm!!

 

[4x4junkie]

I was wondering, if I were to have the gears in my Ranger changed from 4.10's to 3.73's, would it even be worth it in regards to helping my MPG's and engine noise due to the lower RPM's? If I'm at 2500 RPM while cruising at 70 MPH, any idea what they'd drop to with 3.73's?

For the record, I'm not whining about life with my truck. I'm just wondering if this would be something worth doing to allow me to enjoy it even more.

2500 RPM at 70 is pretty low RPM. You'll gain nothing by going lower (infact, you may hurt MPG).

What engine you have? If its anything but the 4.0L, you might gain MPG by going the other way to 4.56 gears.

 

[Tribefan]

Sorry for leaving out that info. I have the 4.0 with 5 spd auto. I don't recall the tire size exactly, but they're not the 31 inch tires that are optional on the FX4, it's the tires that come on the 16" wheels. 255/70's maybe?

 

[LearjetMinako]

I would leave the 4.10 in. 3.73 with 255/70R16 tires will most likely hurt MPG. 2,500 RPMs @ 70 mph is actually ideal. My Ranger turns 2,500 RPMs @ 70 mph, but its has a 2.3L with 225/70R15 tires. If I go any bigger tires, say 235/75R15, I would need to swap the diff for a 4.10 to regain power.

 

[exbass94]

I think I have the same size tires as you, and I have a 4.0, auto, and 4.10 gears, and I run about 2500 rpm at 70 mph. With only highway driving, I usually get about 17.7 mpg. If I slow down to 60-65 mph, (2100-2300 rpm) I can just manage to break 18 mpg. I bet if I slowed down to 55 mph, I could squeeze out a little more mpg but it gets dangerous going down I-95 that slow, as the flow of traffic is about 75-80 mph. IMO, not worth it, enjoy your acceleration.

 

[JFA_Spyderman]

+1, stay with the 4.10s

 

[mhughes165]

I was going to tell you I'll go out and run mine down the road but for one you didn't say what size tires you have and 2 I don't think I can get up to 70.
I could tell you at 50 but again you didn't say what size tires you have and seeing as I am running 31's unless that is you are roo
Dave

how can u not get goin 70?? i used to burry the needle on 33" boggers with 3.73's

 

[MAKG]

'Cause either his truck is broken or he's a chickens**t.

I can get up to 70 MPH in my low-revving 1972 fullsize Chevy with its 3.73 gears and no overdrive. I've taken it up as high as 80 MPH and not run out of air, despite it's dinky (1 7/16) single barrel carburetor. It's kinda loud up there, but it can do it.

And the Exploder will VERY easily do 70 MPH (every day) with 31s and 3.54 gears. I won't take it over 80 due to the suspension, but the engine and drivetrain will certainly do that with ample margin left over.

Oh, and if you do take those 4.10s out, can I have them?

 

[Sevensecondsuv]

If I'm at 2500 RPM while cruising at 70 MPH, any idea what they'd drop to with 3.73's?

That's simple:

New RPM = Old RPM x Ratio of new gears to old gears

New RPM = 2500 x (3.73/4.10)

New RPM = 2500 x (0.9098)

New RPM = 2274.4 ~ 2275 RPM's at 70 MPH with 3.73 gears and same tires.

 

[Tribefan]

Thanks for all the feedback guys. I guess it wouldn't be worth it to change the gears. It was worth a shot.

 

[AllanD]

If you can change them yourself it MAY be worth it

If you drive at the same speed it might not make much difference, but then again
with a 4.0 5sp manual with 4,10 gears and 235/75-15 tires that I can get 20mpg at 65mph, but that drops to 17mpg at 75mph.

Why is this? because a 4.0 goes from tolerably efficient to complete pig in just over 300rpm.

a 4.0 is a pig at 2500rpm or above

a 2.9 run is a pig below 2700rpm.

a 3.0 is a pig below 3000

Or in short:
DON'T spin a 4.0
You MAY spin a 2.9
You MUST sin a 3,0

I WILL have 3.73's in my truck before my next trip to wyoming.

Nebraska, it's a bitch!

AD

 

[LearjetMinako]

If you can change them yourself it MAY be worth it

If you drive at the same speed it might not make much difference, but then again
with a 4.0 5sp manual with 4,10 gears and 235/75-15 tires that I can get 20mpg at 65mph, but that drops to 17mpg at 75mph.

Why is this? because a 4.0 goes from tolerably efficient to complete pig in just over 300rpm.

a 4.0 is a pig at 2500rpm or above

a 2.9 run is a pig below 2700rpm.

a 3.0 is a pig below 3000

Or in short:
DON'T spin a 4.0
You MAY spin a 2.9
You MUST sin a 3,0

I WILL have 3.73's in my truck before my next trip to wyoming.

Nebraska, it's a bitch!

AD

I guess thats one way to describe an engine.

Lima 2.3L is pretty humble, no matter what RPM's above 1,500