Off-road fuel economy? Getting barely 5mpg

Is this common? I am usually in slick hilly clay so I stay in 4LO to keep the torque up so I can fling the mud off the tires when needed. I will fill up with a bed mounted fuel tank when I get to the woods and I’m already at half a tank after driving 40 miles. Payload is 2 guys with about 800lbs of logging equipment in the bed.

The SR is supposed to be a work truck but how’s anyone supposed to get any work done if they are having to get gas every day or take up a foot of bed space with an external fuel tank?

 

Is this a real question? You’re in 4LO, you’re burning way more fuel do to the higher RPM’s caused by the lower gearing.

 

I don’t spend much time offroad or on trails slow moving in 4x4 but I’d guess that’s pretty normal and to be expected. Did you get better mileage doing the same thing in your prior tundra?

 

5mpg in 4LO seems right.. a buddy of mine has a 4Rrunner with the 4.0 and calculated before and it was about 4.2mpg.. i've never calculated before but I assume the 5.7 would be around the same ballpark if not less

 

Are you idling any or driving the 40 miles straight through?

 

Your mileage drops in half roughly in 4-lo cause the rpm’s go up. Also going slow up and down off-road gets much worse than on road driving. As a side note the base SR models have a small 22.5 gallon fuel tank and the range goes to zero miles remaining with about 5 gallons left so really 17ish gallons of usable fuel. One of my gripes with the base truck if you tow or off-road the range is poor, even highway driving it’s not very far.

 

Welcome to any truck in 4Lo. Especially when you are loaded and going through hills and low traction.

 

I've gotten less than 5mpg when crawling.

 

Lol….

 

Build or buy a high clearance all terrain trailer for the equipment and put a secondary large tank in the bed. Just be sure to rob the local bank before you go fill up!!

 

Bad advice
NEVER ROB THE LOCAL BANK

 

Under 20 MPH you're not doing great on MPG in most vehicles anyway, and if you add the low gearing for torque over efficiency, it's not great. Look at any of the major crawler builds and they all have fuel cans. Low speed high torque means crap economy.

 

True....the gas station has all the money!!!

 

Stay out of 4Lo until you actually need it

 

Slow crawls up hills and such are when you need it to prevent excessive transmission heat, isn't it? In my Tundra if I needed 4x4 but I was going to be sub 15-20 MPH I always ran in 4Lo.

 

Same here. I have more control using the gearing to slow me down. But I guess it's all about which mode you're in. If you're hauling ass like @joonbug then he's rarely in 4Lo. If you're leaving snail tracks like me then you're mostly in 4Lo.

 

Truth. And if I were long travel on tires 35"+ I wouldn't be going slow either. But that's one of those lottery dreams that'll never happen.

 

Wait a truck offroad bad gas mileage. Well shit

 

Wow guess I’m not fast enough lol

 

I'd have to fill up a whole page if I wrote down every one you fast fuckers!

 

hahaha

 

Sounds like we need a @joonbug vs @reywcms race to see who is the fastest!

 

Seems to me that you need to trailer a dedicated off road rig to the area, then you will be starting off with a full tank, better tires, better gears, etc.

 

Perhaps tire chains and 4hi? Not chains, but the newer cable style. Love those in deep snow with ice base and should work similar for clay, maybe?

 

I’m not that fast lol

 

Op, you’re doing the right thing being in 4Lo, the gas mileage will suck. If you drove around in 4hi and overheated your truck, they would all be yelling at you to put it in 4Lo. Your use is extreme compared to most. Probably need to carry some aux fuel cans in the back. I’m a fan of the “motorcross” style fast empty cans, but jerry cans or whatever will work and not take up too much space. 2 or 3 of the 5 gallon cans will be easy to handle and not consume the bed of the truck. Shame there’s no 38gallon tank option.

 

Spinning chains/cables is a bad idea. If they come loose at all you have what amounts to a flail beating the piss out of everything in range.

 

You said it.
Plus, you’re not moving very fast, so airflow through the radiator and to pull heat out of the engine bay is low.

 

Driving through muddy terrain in 4Hi puts a lot of strain on the transmission torque converter. Due to the increase load of churning tires through mud up hills, the torque converter lets the engine RPM raise high enough to push enough power through the drivetrain to overcome that increased load. But the torque converter works as a fluid coupler between the flywheel and the transmission; revving the engine side of that coupler creates fluid friction (as a bad way of simplifying it) between the two halves of the torque converter. The higher the RPM, the higher the friction; the higher the friction, the higher the heat. All of this heat is absorbed by the transmission. While the transmission has a cooler (either external or built in to the radiator) the radiating surface of that cooler is very small compared to a the engine coolant radiator. So once you build up heat in the transmission, it's harder to dissipate.

Putting it in 4Lo puts more mechanical advantage between the transmission and wheels since the transfer case is between the transmission and drive axles. It does this by allowing much deeper gearing between the two - much like shifting to an easier gear on a bicycle. The downside is that know you have to pedal much faster to maintain speed. This also means that everything upstream of the transmission (torque converter and engine) has an easier time creating that power before transferring it to the wheels.

So, yes, you are doing the right thing putting it in 4Lo. And thing about this: the transfer case low range is approximately 2.48 to 1 - meaning the engine/transmission spin nearly 2 1/2 times more than the output of the transfer case. Low ranges multiplies the torque 2.5 times between the transmission and wheels. Hi range is 1 to 1. So, since you are getting 2.5 times the torque, you are 2.5 times the fuel to go the same distance you would in 4hi or 2hi. So 5mpg is pretty alright.