2024 Ram 2500 Tradesman 6.4L - Lower than expected MPG

[21_6.7f450]

Cline didn't the 6.5 come out in the early 1990s? He's got to be thinking 6.2 N/A. With 3.08s and a 700r4,they'd do it empty running 65mph. I saw 1993. I say, nope...unless running downhill full time.

 

[nwjones18]

My Ram 1500 with the 5.7 and 3.92 gears has only gotten 20mpg on one tank in the 6 years I've owned it.. Average from my fuelly ap (30k miles) is 16.5. No way your uncles truck is actually getting that. Your Dad's MPG's sound realistic.

 

[clinebarger]

'92 IIRC? We had a '95 2500 6.5L Suburban in the family for years.....It could get 20 if you stayed out of it.

I had a '97 Dodge 2500, 215HP 6BT with a 230HP fuel plate, It could achieve 20mpg unloaded on flat ground @ 60mph.

Neither could average 20mpg.

 

[Skippy722]

My Ram 1500 with the 5.7 and 3.92 gears has only gotten 20mpg on one tank in the 6 years I've owned it.. Average from my fuelly ap (30k miles) is 16.5. No way your uncles truck is actually getting that. Your Dad's MPG's sound realistic.

Same here except I have 3.21 gears, but I am running 10 ply/E load range tires.

 

[dfarr67]

Never knew a dodge that got great mileage- great power.....but mileage- no.

 

[spasm3]

When I bought my 21 ram 2500, I drove a couple of them.
It seemed to me that the 4:10 rear allowed the truck to go into mds sooner, and stay in it longer, than the ones geared higher.
I have not driven a tank of fuel that did not involve towing, so I don't know city/high mileage unloaded.

 

[demarpaint]

Agree. 20mpg, downhill, after a long bathroom break, maybe.

And a good tailwind.

 

[Rmay635703]

Cline didn't the 6.5 come out in the early 1990s? He's got to be thinking 6.2 N/A. With 3.08s and a 700r4,they'd do it empty running 65mph. I saw 1993. I say, nope...unless running downhill full time.

My 350 gas Suburban 2wd was a pretty consistent 20mpg on the highway.

The c-code 6.2 with a 5sp shift swapped in was mid to high 20’s but if I kept near the speed limit 29mpg was possible.

Back then there was a dramatic fuel economy difference between 2wd and 4wd

After 40 years we shouldn’t be getting in the teens unless you are hauling a trailer.

The engines in trucks today are up to 50% more efficient at BSFC peak compared to motors from the late 90’s and earlier.

 

[Rand]

2020 ram 1500 hemi I can get 18-19mpg if I go 60mph.
Normal driving 15-17.

Cant imagine a 2500 with the 6.4 doing more than that.
The Load range E offroad tires probably don't help either.

After 40 years we shouldn’t be getting in the teens unless you are hauling a trailer.

The engines in trucks today are up to 50% more efficient at BSFC peak compared to motors from the late 90’s and earlier.

Trucks are 50% bigger too.

Maverick probably hauls more than a 1989 f150. gets 40mpg.

 

[21_6.7f450]

What did an 1987 350 Suburban weigh, 5k? I have no idea, that's a WAG. The new crew cab larger gas 4x4 Dodge is probably 7,500lbs. Put 2,500lbs BEHIND the suburban and look at milage again. You will be surprised. The new trucks are heavier.
Thank... for air bags, all those pesky weight adding unnecessary things that reduce milage. A 6.4 Hemi with a zf 8 in a 1987 Suburban WOULD get 20-21mpg without a doubt

 

[Fordiesel69]

Alright so here is the mystery, the uncles 2017 had the 6 speed 66RFE, and when we drove it and got the hand calculated 20 mpg, it never unlatched out of top gear. It seemed to have the torque to stay there. It also had a nice sound like at times the engine was able to do work. We dont need to beleive him, we are the ones that filled up, reset trip meter, drove our trip, pulled back in the same gas pump, filled up again and hand calculated the real MPG, and the dash actually showed more. It was summer blend 87 fuel from shell.

On the 2024 we used a loves station that had a good price on the 87 but im not sure who makes loves gasoline. Here is the issue, the 8SPD ZF tranny was constantly hunting back and forth from 8 to 7th gear at every little dip in the road. The constant hunting never allowed the engine to get into MDS mode. I am very confused. Its like the programmers at FCA do not want to have the engine lug.

Oh another issue I just now thought about. This 2024 is supposed to have 0W-40 and I assume that is what is in there from factory. I think in 2017 it may have specd a different weight. In addition I discoverd the 2024 has dual alternators as it has the snow plow prep package.

 

[21_6.7f450]

I don't believe it. If you are talking about an average of 400+ miles. Nope! She might get 17 under ideal conditions 15-16mpg is more likely. Now if you are talking 20mpg over 20 miles, that's not even close to realistic. I can get a 2021 6.7 F350 DRW 4.10 geared get 32mpg for a 10 mile stretch at 60mph slightly downhill with the tires at 80psi, truck not towing anything.
Edit the F350 has plow package and dual alternators...32mpg oh yea!
My Tacoma only averages 16.7mpg.

 

[Skippy722]

Alright so here is the mystery, the uncles 2017 had the 6 speed 66RFE, and when we drove it and got the hand calculated 20 mpg, it never unlatched out of top gear. It seemed to have the torque to stay there. It also had a nice sound like at times the engine was able to do work. We dont need to beleive him, we are the ones that filled up, reset trip meter, drove our trip, pulled back in the same gas pump, filled up again and hand calculated the real MPG, and the dash actually showed more. It was summer blend 87 fuel from shell.

On the 2024 we used a loves station that had a good price on the 87 but im not sure who makes loves gasoline. Here is the issue, the 8SPD ZF tranny was constantly hunting back and forth from 8 to 7th gear at every little dip in the road. The constant hunting never allowed the engine to get into MDS mode. I am very confused. Its like the programmers at FCA do not want to have the engine lug.

Oh another issue I just now thought about. This 2024 is supposed to have 0W-40 and I assume that is what is in there from factory. I think in 2017 it may have specd a different weight. In addition I discoverd the 2024 has dual alternators as it has the snow plow prep package.

Is it actually shifting or is it coming out of MDS? It’ll unlock and lock the torque converter every time it goes into or comes out of MDS which will show as a bit of a rpm flair. With my aftermarket exhaust it actually sounds like a shift almost.

With the LT E range tires on my 1500 it’ll “hunt” for MDS at highway speed. With the factory p metric tires it would go into mds and sit there at 70, with these Yokohama’s it does NOT like being in mds unless it’s downhill at 50+. On some hills it’ll drop to 7th where before it would stay in 8. Dual alternators won’t help fuel economy either.

 

[Fordiesel69]

It was 306 miles of highway doing 74 MPH.

I pulled up the gear on the display and watched it go back and forth from 7 and 8. I cannot tell you however if MDS activated in 7th. I swear it did.

 

[OVERKILL]

Oh another issue I just now thought about. This 2024 is supposed to have 0W-40 and I assume that is what is in there from factory. I think in 2017 it may have specd a different weight. In addition I discoverd the 2024 has dual alternators as it has the snow plow prep package.

The 6.4L has spec'd 0W-40 since it was introduced.