Engine/Transmission (1998.5 - 2002) MPG std VS auto 3:54, 4:10 difference

[GMichaels]

Ok sold my 93, need a 4wd. looking at a 01 3500 4wd truck but with fuel prices getting crazy every MPG counts.



So figure a 6 speed with 3:54 would be the best chioce for good MPG.



Looks like 4:10 for the same setup will average 1. 5 less.



I need to tow 15k 20% of the time, so figure 3:73 would be a good choice but try and find a truck with that axle ratio.



Like to know how automatics do, and can they hold up towing? lot mre autos that 6speeds out there.



best millage seems to be with a 12v engine as well as fewer problems, was looking for a 98 quad cab with a 12v but for 15% more can get an 01.



So am I right 6 speed 3:54? told when towing I would be stuck in 5th but I can live with that.



Looking for any input...

 

[ToolManTimTaylor]

I didn't think that 2nd gen 3500's came with anything higher (Numericly lower) ratios than that of 4:10:1

 

[Babyfat]

i've seen some w/3:54



mine gets 18 empty (w/4:10)

got 13 on a past trip to GA 1850 miles with 5er 21k gross

 

[.44 mag]

How do you get 18mpg empty!??!?



I've got an '01 2500 4. 10 auto. that I can't get above 14mpg with the best possible conditions. I see from your signature that you've got a DTT trans. Did adding that help with the better mpg?



Thanks!

 

[JWBoothe]

How do you get 18mpg empty!??!?



I've got an '01 2500 4. 10 auto. that I can't get above 14mpg with the best possible conditions. I see from your signature that you've got a DTT trans. Did adding that help with the better mpg?



Thanks!

Our last camping trip up the Cali coast, I got 18. 5mpg going 80mph with 750lbs of crap in the bed.

 

[Huff N Puff]

They do make a heavy duty 2500 2nd gen. alot lighter truck that can tow more than the 3500,You can also use the 3500 with 4. 10 but use taller diameter aluminum wheels. This way you increase the effective final drive and lighten the rotating mass.

 

[DieselRam30]

With a 3500 4x4 with 4. 10s stock, the best I could do empty was around 16. With the mods list in my sig, I can get above 20 if I stay off of the smoke pedal.

 

[NIsaacs]

Per my 02' Dodge brochure, the 3500 HO only used the 4. 10 ratio, the SO used 3. 55/4. 10. On the 2500 models you could get 3. 55/4. 10 with HO or SO.



GMichaels, with the towing you have in mind, I would get the 3500 w/ 6spd. I prefer the 3. 55's but mine is a 2500. The 4. 10's will be ok on fuel if you keep your speed down. Fuel mileage is based more on road speed than gear ratio or rpm. I like the 6spd so much more for towing than the 5spd or auto, that I would get the 6spd and never mind what the axle ratio was.





"NICK"

 

[macdaddy]

They do help!!!

How do you get 18mpg empty!??!?



I've got an '01 2500 4. 10 auto. that I can't get above 14mpg with the best possible conditions. I see from your signature that you've got a DTT trans. Did adding that help with the better mpg?



Thanks!

Performance trannies due help in fuel economy, due to more aggressively pitched stator's.



Mac

 

[trqmnstr]

GMichaels, since you are only towing 20% of the time, I would definitely go with 3. 55. I'd get the 6 spd. I think that would be a good combo. You will probably be stuck in 5th gear when towing but I wouldn't want to be in 6th towing 15k anyway. I think you'll be happy with 3. 55 and 6 spd. You should be able to get around 18-20 non towing with a light foot. That will make up for the 5th gear towing. Just my opinion. Clay

 

[c-hawk]

I don't have experience with 3500's, but the two 2500's below in my sig are as close to the same setup as possible except for the trannys. (Both quad cab, short bed, 4x4, 3. 55's. )



The 02 auto has never done better then 18mpg. Its average is around 17mpg... These numbers were consistent all the way from stock to about 460rwhp.



The 01. 5 6spd stock averaged about 19. 5mpg with a best tank of 20. 2mpg. My first tank with a set of Don M's 1. 2's I got 21. 5mpg. In my opinion that's awesome since i ran it harder than normal since i was playing with the new power. I'm pretty sure i will see even more of an improvement when i return to my normal driving habits.



So in my two trucks with similar driving styles and similar city/highway i see about 2. 5mpg better with the manual then with the auto.



Chris

 

[Mundgyver]

I do not have a 3500 but I do have a 2001 - 2500 H. O. 6 Speed with 3. 54 gearing. I run 285 16s for tires on the stock rims. With 7,000 lbs behind on the bumper at 65 mph I get 18. 5 mpg. With a 15,500 goose neck and a GVW of 23,000 even for the whole I get 15. 5 mpg at 65 mph. Empty at 65 mph I get 23. 8 mpg on the freeway. These are consistant repeatable fuel numbers that I get without any effort. If I trail a tractor trailer about 30 yards back I can improve my empty mpg by about 3, but it is alot of concentration that I am not prepared to do all the time. I suppose if fuel gets to $5 a gallon I will start thinking about drafting more.



According to my owners manual I can haul the same loads as a 3500 configured with a 6 speed with one exception, and that is if he has a set of 4:10's installed then he has me by what ever the extra tires support for weight which is around 1300 lbs.



Go for the 6 speed if you want the mileage. I just installed my fuel cooler and all indications are my mileage will be better than 24 now. I will know this next week end when I cruise down to Corvallis, Oregon as that is a solid 200 mile run for me. I run with my Edge Comp in Level 1 all the time and I have a set of 275's installed.



The truck has 150,000+ turns on it and I still have my original VP and clutch and brakes.

 

[Mundgyver]

Here is what 23,000 GVW looks like. The trailer weighs in at 4,000 by itself and there are 56 gas bottles loaded up at 205 lbs each for a total of 11,480 lbs The truck by itself came in at 7,520 lbs.

 

[trqmnstr]

Mundgyver, how did your truck pull that load? Don't tell me you didn't know it was back there.

 

[bkroupa]

Just as a reference, my 98 12v 2wd, 5spd, 245/75's, 4. 10 geared got 18-19 running on the hwy 70-75 mph dead stock, I went to 285's & it didn't really help, I had the timing bumped & started getting 21 mpg consistantly, I swapped out the 4. 10's for 3. 54's & routinely get 22. 5 or better on my normal commute.

 

[Mundgyver]

I knew it was there for sure Oo. I had good power with no problems. These kind of loads are the ones that prove to me why I invested in an exhaust brake Pulling was not a problem, course your not going to be real fast but then again I was able to step up to the plate when I needed to pass with no problems. We just take our time and try not to get in a hurry.



Speed is not the problem with heavy loads, it's all about the stopping



What's that saying, oh yea, It's not the sky-diving with a faulty chute that kills you, it's the sudden stop at the end



If I pulled for a living, I would have a 3500 with a Kederman air ride. Oo.

 

[ToolManTimTaylor]

Here is what 23,000 GVW looks like. The trailer weighs in at 4,000 by itself and there are 56 gas bottles loaded up at 205 lbs each for a total of 11,480 lbs The truck by itself came in at 7,520 lbs.

And there is what 4 tie downs holding that all together!!! That back pallet has 18 missles on it = 3690 lbs held in place by one tie down ... dude pow zing.

 

[Mundgyver]

Each pallet is bundled with a single 2,000 lb ratchet strap to hold the pallet together while loading. Over the top are 8 inch wide yellow straps rated around 30,000 lbs. I figure that if I was illegal the cops at the scales would have ticketed me but being that they did not and did look at the load, then I don't see a problem Missles are self propelled any way and every bottle here is empty with no fitting. I figure if these yellow straps can be used by an 18 wheeler to hold down 6 bunks of plywood, then they ought to hold a few bottles with no problem

 

[JMHodge]

Upper Limits 26 MPG at 50mph, 25.3 at 55mph (so far)

:{ With the Diesel prices going up and the future and looking like you will need a co-signer if you fill up.

I decided to see just how much mileage I could squeeze out of my 99 RAM. I have done some radical things to her gearing with the two trannies and tall tires. My mods will never pay for themselves no matter how high Diesel goes. I can only tell myself that doing them the engine/trans will probably save 20% wear which would be considerable if I live long enough to log 1,000,000 miles on her (138,000 and counting). Oo. The truth is I did it because I love my truck and just wanted to do it... . don't really need any excuse.



Before anyone falls over and faints that my RPM's are too low and that I need to pick a lower gear and speed up the engine ... and I'll get better mileage. I know... I have 8 beautiful gears and love them all. So I have been there and tried that ... . it simply does not work... if you are still within the power-band. The faster the engine runs the more fuel it burns... probably something to do with physical laws and air/fuel mixture to produce required torque. If I stay within the power-band for the load I am putting on the engine (running empty and on flat ground) pre-turbo EGTs remain low, engine doesn't growl anymore than a Kenworth and there isn't any tell-tail lugging vibration. If EGT's go up and lugging is felt, I downshift... as I have exited the power-band.



Double-overdrive gives you 50mph at 1000rpm and 55mph at 1100 rpm with the 3. 54 and BFG 315's. The engine mods are pretty mundane compared to a lot of the TDR members but she still has plenty of torque to do these speeds smoothly with no lugging on level ground. My pre-turbo EGT's ran between 700F and 800F.



This is my experiment for the upper envelope of fuel mileage, which intersects at the lower limit of the engine's power-curve (almost at idle). This is not anything I recommend to anyone especially at the 50mph limit where my computer display shows fuel consumption to be 26mpg.

However at 55mph my computer display shows fuel consumption to be 25. 3mpg and there is ample torque to conquer small rises with EGT's only going up to 800F. I just may try this speed for a while rather than my normal 65mph. If any of you TDR members buzz by me. . give me a wave... I'm just not in a hurry to get to work or to get home. I'm just enjoying my truck wherever it's at.





Black99 5-spd /Gear Vendors 2 spd, BFGoodrich 315's, 6 inch longarm lift, Superchip,Volant hi-performance cold air intake, FASS, rebuilt injection pump (yes it died), 5 Westech guages,(dueltrans temp, duelEGT/Boost, fuel pressure), High Per Kevlar cluch, 4"ss exhaust, 5"Bull Horn stacks, custom light bar 6 Black Magic's, massive Trail-Ready frt bumper/Brush guard (half cowcatcher and half basket ball goal),2 510 PIA Fogs, 12,000lb. WARN, fabricated 1/2"plate back bumper/swing-out tire carrier... thick as a backhoe’s blade…. got to be careful when backing up ate a cougar once in a parking lot. Pretty heavy and pretty dirty aerodynamically, a lot like pushing a locomotive down the road…. at least it looks like one. Hope to up the HP in the future with a new turbo and Edge chip.