3.73 vs 4.27 and RLD

[Owl]

I got a Base 2Dr with V6/auto. If I could have got the locking diff... I would have. Every now and then I wish I would have upgraded to a Big Bend just for that, but that would have cost about $3500 more.

I'd get it if I were you. I don't drive off road (hardly at all), but I still wish I had it.

I get 22-24 MPG, I don't think that would really change much with the 4.27 Rearend.

And... when you sell... I think it is a valid selling point.

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[cb123]

I was told as long as you keep all 4 tires on a surface you probably do not need lockers. If you go over rocks and get 1 tire off the ground you need lockers. If not why diminish your gas mileage every mile you drive for no reason.

 

[Owl]

Just an FYI -- I've got a Base 2Dr, auto/V6 with the 3.73. I put 32s from an OBX on it, and it looks good, and runs really nice. AND... I felt comfortable doing it because 32s are stock on an OBX with 3.73. I would never consider 35s, because they are heavy, noisy, and only give you 1.5 inches more of clearance (but that's just me). I'm mostly a highway rat.

I get 22-24 MPG with it on the highway, and that includes going up (and then down) a 1500 foot climb (and then back), at about 68 MPH on a 90 mile trip I make each Friday.

Even on the climb (two 3/4 mile hills) the engine/trans combination is fine, and I really don't think it goes into turbo mode much (if at all). It IS a 10 speed after all.

However, if I could have gotten rear eLocker on the Base and 4.27... I WOULD HAVE STILL DONE IT... just for the heck of it, even though with one wheel off the ground (or spinning) you can still get traction by feathering the brakes a bit.

Maybe its just the cool factor to me.

Maybe you can get some 4.27 with 32s on them to give you some MPGs to compare with what I get. That would be the ONLY REASON I'd not get the 4.27/eLocker combo.

 

[Jazer]

Also the 3.73 isn't terrible for the base gearing, imo. My friend just bought a 2024 Jeep Sahara and it has 3.4x gearing.. (I'm not familiar with all of Jeeps lineup, but just to put that out there for comparison sake).. so it's not a terrible place to start by any means.

If the 3.73 makes the motor go into boost to keep highway speeds, it will hurt your fuel mileage.

I do not experience this at all? I can easily maintain speed with my 2.7/3.73 pairing with 33s, without boost. Maybe the 2.3 struggles?

 

[Jsullivan]

The lower gear will make in town driving easier, a little more pep off the line.

I'm actually surprised they offer the 3.73 with these heavy, non-aerodynamic bricks.
If the 3.73 makes the motor go into boost to keep highway speeds, it will hurt your fuel mileage.
Because of that, there's a strong possibility the 4.27 is the better gear all 'round on the Bronco, compared to the 3.73.

Base 2.7, 3.73, 33" tires.
Drove to work this AM in 8" of snow. Used slippery mode cruised at 45 mph, the tach said 1200 rpm.
I had plenty of torque.
I get 23 mpg average in summer.
If they would have offered the 3.73 with a locker, like they do on the F150's, I would have gotten the option.
Unless you do serious off roading you will never miss not having it.
I do have axle back dual exhaust and the Roush intake and tune.

 

[35tires]

If it's an option, get it. 4x4 is just better with a rear locker. You may not need it, but it's more than just an add on and well worth the modest price.

 

[Fivefingerheist]

Base 2.7, 3.73, 33" tires.
Drove to work this AM in 8" of snow. Used slippery mode cruised at 45 mph, the tach said 1200 rpm.
I had plenty of torque.
I get 23 mpg average in summer.
If they would have offered the 3.73 with a locker, like they do on the F150's, I would have gotten the option.
Unless you do serious off roading you will never miss not having it.
I do have axle back dual exhaust and the Roush intake and tune.

With how aggressive 4.46 gearing is in the Badlands auto (non-SAS). I'm actually glad it's not any lower. Although, that's only what a 5% difference from the lowest factory at 4.7? I average 16, but I have a heavy pig now.

 

[HoosierDaddy]

Maybe the 2.3 struggles?

I had plenty of torque.
I get 23 mpg average in summer.

LOL, I forgot we are talking about the 2.7.
I'm in the wrong thread, I have only driven 2.3's.

Interesting info though.

I'll put this out there for anybody reading along:

The 2.3 loves to spin. I get the best fuel mileage at around 2500 to 2700 rpm.
For my manual Base on 35's and 4.46, that means running it in 5th gear at 78 mph. (21+ mpg)
It rarely goes into boost at those rpms.
In 6th gear, it SLAYS the fuel mileage.

The Badlands 2.3/4.46/auto/33's has yet to hit 20mpg. Usually around 18.6 on my highway trips.
It sees a pound or three of boost fairly often, any slight incline etc etc.
It runs in the lower 2k rpms at 78 mph.
If I'd had a choice of lower gears, I would have taken it.

 

[Brian_B]

LOL, I forgot we are talking about the 2.7.
I'm in the wrong thread, I have only driven 2.3's.

Interesting info though.

I'll put this out there for anybody reading along:

The 2.3 loves to spin. I get the best fuel mileage at around 2500 to 2700 rpm.
For my manual Base on 35's and 4.46, that means running it in 5th gear at 78 mph. (21+ mpg)
It rarely goes into boost at those rpms.
In 6th gear, it SLAYS the fuel mileage.

The Badlands 2.3/4.46/auto/33's has yet to hit 20mpg. Usually around 18.6 on my highway trips.
It sees a pound or three of boost fairly often, any slight incline etc etc.
It runs in the lower 2k rpms at 78 mph.
If I'd had a choice of lower gears, I would have taken it.

A lot of it depends on what tires you are running and if you have a lift or not and how much weight you are hauling around (armor, winches, etc)

My 2.3 Manual, with 35's and a 2.5" lift and the 4.46 gearing - 6th gear is worse than 5th gear because of the torque. At about 75MPH, 6th gear sits at a nice 2k rpm (give or take), but it also sits at around 2psi boost the entire time. Whereas 5th gear will sit around 2.8k rpm, but zero boost, and that is a bit better mileage. The difference there isn't much, but measurable - 17.9 vs about 18.1

I don't get anywhere near your 21+ MPG, even though we have the same drivetrain

 

[Snacktime]

You want the 4.27 with a locker for other reasons than gearing. The 4.27 gears are not welded to the carrier and you get different length rear shafts with the locker. Long term servicing will be cheaper and parts more available for locking rear end as most of the broncos made have a rear locker.

For me the gearing is a must have as the Bronco is a Brick and you need every inch of leverage you can get. Bronco get great mileage at 55-65mph after that its damage control. With a bad head wind you can be pulling 5-7psi of boost down shifted at 3000 rpms doing 55mph.

 

[Brian_B]

You want the 4.27 with a locker for other reasons than gearing. The 4.27 gears are not welded to the carrier and you get different length rear shafts with the locker. Long term servicing will be cheaper and parts more available for locking rear end as most of the broncos made have a rear locker.

This is true - all the aftermarket stuff is going to be aimed at the ELD-fitted rigs. And just about everything about the ELD-fitted rear end is just-different-enough from the standard one.

Kind of like most of the aftermarket stuff is geared towards the MIC hard top, the Modular bumper, etc.

 

[mbc15]

4.27 and rear locker it is!

 

[Beach_Bum]

LOL, I forgot we are talking about the 2.7.
I'm in the wrong thread, I have only driven 2.3's.

Interesting info though.

I'll put this out there for anybody reading along:

The 2.3 loves to spin. I get the best fuel mileage at around 2500 to 2700 rpm.
For my manual Base on 35's and 4.46, that means running it in 5th gear at 78 mph. (21+ mpg)
It rarely goes into boost at those rpms.
In 6th gear, it SLAYS the fuel mileage.

The Badlands 2.3/4.46/auto/33's has yet to hit 20mpg. Usually around 18.6 on my highway trips.
It sees a pound or three of boost fairly often, any slight incline etc etc.
It runs in the lower 2k rpms at 78 mph.
If I'd had a choice of lower gears, I would have taken it.

You left out one piece of important information - Bronco vs. Chonco.

 

[RHeinz]

I use my rear locker frequently when off road, even when four wheel drive is not needed.. I do this to minimize trail damage. We all need to think about treading as lightly as possible.

 

[Black_Stallion13]

Get it for resale value if nothing else. The gas mileage with different gears won’t make that big of a difference. I have 4.46 gears with the manual and still got 23 combined with the stock Bridgestone tires that come on big bend/OBX.

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