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Range / fuel consumption in 4-Lo

penns_woods

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I took my 5.3 L out on the trails yesterday. One 3-mile section was fairly gnarly, with some steep slopes and hard-packed, slippery, wet clay, so I needed to descend carefully and the climbs back out were pretty fun. I used 4-Lo, mostly staying in L1 or L2.

For the out-and-back on this section (6 miles overall), I got 3.3 mpg. Is this what I can expect from the Boss? That's not a lot of range on a 24 gallon tank.

What is your experience on the trail with your Trail Boss?

Thanks!
 

Jmzvet

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That certainly doesn’t seem normal. From what you described, I doubt you used much throttle at all at those slow speeds.
 

Remanaz

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Idling uses a lot of fuel. Did you have a lotofno moving times during that fun.
 
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penns_woods

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Idling uses a lot of fuel. Did you have a lotofno moving times during that fun.
That certainly doesn’t seem normal. From what you described, I doubt you used much throttle at all at those slow speeds.
You're right. I didn't use much throttle. One thing I didn't like what that L1 was too low of a gear, and would rev too high, but L2 was way too high of a gear, and would go too fast for the surface of the track. It left me wishing for a regear. :)
 
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penns_woods

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Idling uses a lot of fuel. Did you have a lotofno moving times during that fun.
Yes, there were a few minutes of idling during the trip. Once was I stopped to let the tranny cool because it was up to 225 and I wasn't liking that very much, either.
 

PHXPHOTOG

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In my experience there is no way that can be accurate. How was it calculated? I suspect you zeroed trip meter and that was what it said after 6 miles? Those MPG meters are not that accurate, especially when your not driving in "normal conditions". I barely use any gas at all when off road. It's mathematical, no matter what your doing, to push that much gas into the system the throttle has to be open enough to do it. When off road on a gnarly trail in Lo 1 & 2 your truck would blow up if you had your foot in it enough to burn that much fuel. I think it's just the meter reading its estimate. They are not actually "metering" the flow of gas.

Which transmission do have? I have the 10 speed and love it. When off road, especially in 4wd Lo, i operate the column shifter button almost like its a paddle shifter I am on it so much. I can't imagine there being that much difference between L1 & 2 even with the 8 speed? I can't imagine how you feel that big a difference between L 1 & 2. It should only be a slight difference.

I am pretty old school and control my truck in manual modes most of the time. But there is a time to trust tech and auto modes. Three miles of trail so gnarly it required L1 & 2 with 2 being too high is some hard core off roading. I don't want offend with unsolicited advice but I can explain my way. When descending my trany is always in manual so I can pick the gear. When climbing, especially in anything loose like mud or clay I use auto to let the truck shift on it's own. I do that for two reasons. One, the tire RPMS will not be limited, it will upshift when necessary to help you dig better. Two, it protects the engine and transmission. If you break traction in a very low gear and keep your foot in it all your doing is tacking it out to red line and limiting RPMs at the wheels. These new transmissions are far better than I am at gear selection in some conditions.

I can assure you your going to average much more than 3 MPG off road.

Kind Regards,

Steve
 
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PHXPHOTOG

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I am baffled by your comment about the big difference between L1&2. Could you have been referring to the difference between 4wd hi and 4wd lo? That is supposed to be a huge difference. But in both ranges you still have your full set of gears available to shift automatically or manually. I can explain further if you like. I don't want to offend.

Steve
 
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penns_woods

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I am baffled by your comment about the big difference between L1&2. Could you have been referring to the difference between 4wd hi and 4wd lo? That is supposed to be a huge difference. But in both ranges you still have your full set of gears available to shift automatically or manually. I can explain further if you like. I don't want to offend.

Steve
Hi! No offense on either part. Thank you for your replies and interest! I have the 5.3L with the 6 speed.

I did use the odometer for this rather unscientific test. I know it's not very accurate, and usually I check actual gas mileage at the pump on any vehicle. Since this was such a short piece (6 miles), with a gas station 15 miles away, there was no real way to get a decent trail reading on this segment other than the odometer, so I tried it. As mentioned, I have the 6 speed transmission. I was in 4-Lo the entire time. Additionally, I was using gears L1 and L2 from the column shifter. My point about the gearing being strange was that in L1 of course it crawls. In L2 it went way too fast for the trail. It was rutted out and had a lot of deep depressions and decent sized rocks such that you have to watch your rockers here and there. The L2 gear was wanting to go way too fast, even with minimal throttle. It just felt a little strange. I only just acquired this truck, so I am not used to it yet. The L2 gear was just too quick for the conditions, but L1 was too slow. It was annoying. I was left wishing it was geared a bit differently, and I don't care for the severe angle of the pedal in this case. It's quite tiring compared to the other 4x4s I have owned. The L1 gear is a real crawler, of course, but L2 was too fast for this place. I couldn't get into a decent "goldilocks" mode to have a good time there. Perhaps the 8 speed and 10 speeds fare better in this circumstance. In my case, there is a pretty big difference between L1 and L2.

By the way, the vehicle's computer is definitely monitoring the fuel flow rate. They have to do this, and they are measuring microliters per second of fuel flow to the injectors. 100% true. The "metering" calculation is known to be off, usually around 5%, but it's not as bad as we would think. All modern vehicles do this. It is not really a guess, but also not 100% accurate.

For example: HOW FUEL MASS IS CONVERTED TO MILLISECONDS ON MODULAR ECUS
Another: A Deep look at Accurate Realtime Fuel Use from Data Logger (Instant MPG)
 
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Trail Brian

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Man I dunno ...... I've been wheeling since the mid 70's and If I have an Auto I use it... ? (unless going down super steep then I downshift) I have had a 5.3 with a 6 speed... In my opinion I would keep that tranny in Auto... I had overheat issues in mine no matter what I did... I had considered a tranny cooler...The 10 speed is a completely different animal mated with a cooler its bullet proof.. at least for me...
 
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penns_woods

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Man I dunno ...... I've been wheeling since the mid 70's and If I have an Auto I use it... ? (unless going down super steep then I downshift) I have had a 5.3 with a 6 speed... In my opinion I would keep that tranny in Auto... I had overheat issues in mine no matter what I did... I had considered a tranny cooler...The 10 speed is a completely different animal mated with a cooler its bullet proof.. at least for me...
Thanks for the advice. This 6 speed is a strange one. The 225 degrees was not exactly getting me super happy, but at least I can pull over and fry bacon on the housing from time to time.
 

Trail Brian

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Thanks for the advice. This 6 speed is a strange one. The 225 degrees was not exactly getting me super happy, but at least I can pull over and fry bacon on the housing from time to time.
the shit show started when I had my 50 K tranny service.. they flushed it and replaced filter etc...3 days later the tranny had a major failure....rebuilt it and never was the same, heavy downshift at stops etc etc overheated several times to 275.. literally shuts down most of the truck...two dealerships couldn't figure it out...sold it for the Trail Boss...dunno If they ever figured it out... I have learned since then Chevy has three different types of tranny fluid depending on the 6, 8 or 10 speed... ? hmmmmm.... so 225 isn't too bad... tranny cooler ?
 
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penns_woods

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the shit show started when I had my 50 K tranny service.. they flushed it and replaced filter etc...3 days later the tranny had a major failure....rebuilt it and never was the same, heavy downshift at stops etc etc overheated several times to 275.. literally shuts down most of the truck...two dealerships couldn't figure it out...sold it for the Trail Boss...dunno If they ever figured it out... I have learned since then Chevy has three different types of tranny fluid depending on the 6, 8 or 10 speed... ? hmmmmm.... so 225 isn't too bad... tranny cooler ?
I guess I have to add an aftermarket cooler to it. There's no way I'm wheeling for hours at 225+. Wow. Thanks for the heads up!

This is a very informative thread about the subject:
High Transmission Temperature (GM Trucks)
 

PHXPHOTOG

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A 6 speed, that helps explain the difference. I thought all TBs had the 8 or 10. I have run 4 speeds off road and always wished I had more range. The 10 speed is like a whole new playground. I am loving it and no heat issues so far. I believe it comes with an external cooler on my 2021.

Did you try hill decent? Mine works well. It sets the speed at the speed of travel when you push the button. Then you can dial it up and down using the cruise control dial on the wheel. I have a 2021 5. LT TB 10 speed.

Steve
 
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penns_woods

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A 6 speed, that helps explain the difference. I thought all TBs had the 8 or 10. I have run 4 speeds off road and always wished I had more range. The 10 speed is like a whole new playground. I am loving it and no heat issues so far. I believe it comes with an external cooler on my 2021.

Did you try hill decent? Mine works well. It sets the speed at the speed of travel when you push the button. Then you can dial it up and down using the cruise control dial on the wheel. I have a 2021 5. LT TB 10 speed.

Steve
Yeah! The hill descent is pure magic. I love it! I tried in deep snow a few weeks ago (10" or so), and then on some steep wet clay and it worked a charm in both cases. Thank you for the tip about the cruise control adjustment! I'll try that. Good to know.

Maybe I should put a 10 speed in here. I'm definitely willing to do it for a better experience. What do you think?

Thanks!
 
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