Well, my dad has decided on the 2001. 5 Dodge 2500 Quad Cab 4x4 with the HO Cummins and the Six Speed. He told me he read in the TDR that the Six Speed gets better fuel economy with the 4. 10 gears than the 3. 54s. Is this true? He doesnt tow much, if anything, and the truck is mainly a highway cruiser used for road trips. Which ratio is best for fuel economy first... power second using the HO motor and the 6 Speed manual??
-
TDR Magazine subscribers receive more than the magazine! You also gain additional forum privileges!
Details here: TDR Privileges
Subscribe to TDR Magazine here: https://www.tdr-online.com/
What ratio is best with the HO Cummins/6 Speed?
- Thread starter Archive
- Start Date
Attention: TDR Forum Junkies To the point: Click this link and check out the Front Page News story(ies) where we are tracking the introduction of the 2025 Ram HD trucks.
Thanks, TDR Staff
- Status
Rambill,
75 mph I am doing a little over 2k rpms with 6spd and 3:54's.
I think the 4:10's are fine if you are towing heavy loads (12K plus)but for what you want I would diffently go 3:54's.
------------------
2001 4X4 ETH 6 spd, QC, SLT,SB, 3:54, Flame Red,camel tan leather, 4" exhaust turbo back, EGT,boost guages, Stage III A's, Edge Products Module, Line-X bedliner.
License Plate "1QIK4X4"
-------------------------
Project that got way out of hand: total "BOMB"
95 Wrangler 4. 0L, NV4500, Reverse cut Dana 60 rear 44 front, Altas II, Quarter Eliptic suspension in rear, coils up front, Warn 10,000 lb to turn me right side up and the list goes on!
75 mph I am doing a little over 2k rpms with 6spd and 3:54's.
I think the 4:10's are fine if you are towing heavy loads (12K plus)but for what you want I would diffently go 3:54's.
------------------
2001 4X4 ETH 6 spd, QC, SLT,SB, 3:54, Flame Red,camel tan leather, 4" exhaust turbo back, EGT,boost guages, Stage III A's, Edge Products Module, Line-X bedliner.
License Plate "1QIK4X4"
-------------------------
Project that got way out of hand: total "BOMB"
95 Wrangler 4. 0L, NV4500, Reverse cut Dana 60 rear 44 front, Altas II, Quarter Eliptic suspension in rear, coils up front, Warn 10,000 lb to turn me right side up and the list goes on!
The tow rating with the 2500 is the same regardless of gear ratios. I have the 3. 54s and for all around driving they work well. I also pull a 7000lb TT and have had no problems with the gears. I average about 16-17 in town and can get 20+ highway. I only have 2900 miles on the truck. The power and mpgs will improve with breakin. If you intend to pull a lot of weight guite often then the 4. 10s may be a better choice.
------------------
2001 HO 6spd,Quad cab,LWB,4x4,Flame Red,all options except for leather,Westin Brushguard/Push bar,Painless wiring,Radio Shack CB( so what it works},my own designed CB mount,Smittybuilt nerf bars,NW Custom rocker covers(more to come)
------------------
2001 HO 6spd,Quad cab,LWB,4x4,Flame Red,all options except for leather,Westin Brushguard/Push bar,Painless wiring,Radio Shack CB( so what it works},my own designed CB mount,Smittybuilt nerf bars,NW Custom rocker covers(more to come)
Rambill - from what I've read and the results of driving at different speeds, rpm's and gears with trucks as well as the the fuel rate graphs that I have read. My opinion is that the SPEED of the LIGHTLY loaded cummins powered truck down the road makes much more difference in mileage than rpm. Example by driving at 75 instead of 65 could require as much as 25% or more horsepower. More horsepower more fuel. this said I would agree with Mike V and choose the 3. 54 unless towing HEAVY loads most of the time. with the 3. 54 you can still move a house and lower rpms relate to longer engine and drive train life. also you may want to read pg57 issue 27 of TDR.
sorry for the marathon post!
------------------
"Have you driven OVER a phord lately"
2001 2500 BRT WHT SPORT QUADCAB 4X4 ETH 3. 54LSD TRLR CMPR PKG ALL OPT XCPT LTHR
I went w/ 3. 54's (DMD) especially once I finally convinced my dealer that Suregrip (DSA) was available w/ 3. 54's!
Thx Gang!
The only thing my rig's hauling is "A" and I had no desire to lower my cruising speed or reduce my top speed for that matter.
Boils down to intended usage I reckon.
Good Luck. Oh yeah, a preliminary welcome to the ETH/DEE waiting club. See ya on the other side.
Thx Gang!
The only thing my rig's hauling is "A" and I had no desire to lower my cruising speed or reduce my top speed for that matter.
Boils down to intended usage I reckon.
Good Luck. Oh yeah, a preliminary welcome to the ETH/DEE waiting club. See ya on the other side.
I have a 5spd. with 4. 10's. I did a test of driving a week not exceeding 65 MPH and driving a week at higher speeds not exceeding 80 MPH. My truck definatley runs more efficient at the higher speeds. The couple of times I have tried this I have seen as much as a 2 MPG difference.
I average 17-18 highway with my truck empty running at higher speeds.
I averaged 16-17 by not breaking 65 MPH.
Beats me... .
I average 17-18 highway with my truck empty running at higher speeds.
I averaged 16-17 by not breaking 65 MPH.
Beats me... .
I get 20. 5mpg consistantly around town. Contrary to Joe's surprise! 
#ad
However, with the 4. 10 ratio, I only get 10. 5mpg towing our 4,400 lb TT 70mph/2500rpm. If I run 65mph/2300rpm, I get 13. 5mpg. Havin't tried 60mph/2100rpm for any length of time. With my previous '95 auto/3. 54, I got consistant 18. 5 in town and anywhere from 13. 5-17mpg towing 70 and 58mph respectively. All things considered, I like the towing performance of the 4. 10 ratio at highway speeds. Boost stays up and response is imediate. Our TT only weighs 4,400 lbs but wind resistance is all there.
------------------
98 2500 CC 4X2 12v 5spd 4. 10
97 Dodge Stratus 150HP
92 Harley Fatboy, Dynojet fuel management, Supertrapp 2-1
#adHowever, with the 4. 10 ratio, I only get 10. 5mpg towing our 4,400 lb TT 70mph/2500rpm. If I run 65mph/2300rpm, I get 13. 5mpg. Havin't tried 60mph/2100rpm for any length of time. With my previous '95 auto/3. 54, I got consistant 18. 5 in town and anywhere from 13. 5-17mpg towing 70 and 58mph respectively. All things considered, I like the towing performance of the 4. 10 ratio at highway speeds. Boost stays up and response is imediate. Our TT only weighs 4,400 lbs but wind resistance is all there.
------------------
98 2500 CC 4X2 12v 5spd 4. 10
97 Dodge Stratus 150HP
92 Harley Fatboy, Dynojet fuel management, Supertrapp 2-1
<font color=blue>Welp I don't have a 6 speed, but just thought I might "add" something here. If you intend to go with bigger tires down the road might want to factor that in.
I currently have 4. 10 ratio in my Auto and I tow nuthing. My reasoning for purchasing the 4. 10 from the factory is I will lift the truck and go with 35 to 36" tires which will "lower" my ratio to between 3. 73 and 3. 55 (depending on which tire I decide on) I was trying to "save" my self some money so I wouldn't have to gear swap down the road. I currently get about 17. 5 to 18mpg highway 70mph. But I also "hotrod" it alot around town with overdrive locked out to let people hear me coming (4" exhaust).
Which gears are right for you all depend on what you have in mind for the truck. If its possible (with ETH might be hard to locate 2 of them) test drive one with with 3. 54 and then hop in a 4. 10 gear ratio truck. See which one you like the best.
------------------
[This message has been edited by KatDiesel (edited 08-30-2000). ]
I currently have 4. 10 ratio in my Auto and I tow nuthing. My reasoning for purchasing the 4. 10 from the factory is I will lift the truck and go with 35 to 36" tires which will "lower" my ratio to between 3. 73 and 3. 55 (depending on which tire I decide on) I was trying to "save" my self some money so I wouldn't have to gear swap down the road. I currently get about 17. 5 to 18mpg highway 70mph. But I also "hotrod" it alot around town with overdrive locked out to let people hear me coming (4" exhaust).
Which gears are right for you all depend on what you have in mind for the truck. If its possible (with ETH might be hard to locate 2 of them) test drive one with with 3. 54 and then hop in a 4. 10 gear ratio truck. See which one you like the best.
------------------
- <font color=blue>
- Eric D. Howard -
#ad
- BOMB'er! -#ad
- TDR Member since April 8th, 2000, Rancho 9000 shocks - 2001 Dodge Ram 2500 HD 4x4 SLT Auto Reg cab Cummins Turbo Diesel 4. 10 gear ratio LT265/75R/16 tires
- Patriot Blue Pearl Coat, Agate interior, Leather seats EVERY option, Silencer Ring AWOL, Trans Go Shift Kit
- JRE 4" Exhaust, "Hot" PowerEdge, Autometer UltraLite Gauges (EGT, Custom Boost, transmission temp), K&N Airfilter</font>
[This message has been edited by KatDiesel (edited 08-30-2000). ]
It really depends on your expected cruising speed- I'm running 3. 54 with 5 speed and stock 2001 height tires. As Donnely indicated, I can definately see the mileage drop off at 2k rpm which is 70MPH- much slower than local traffic and even posted speed limits in areas. After driving my buddies 4. 10/ 6 speed with gear vendors on a long trip I intend to move up 2-3 inches in tire diameter next time around. I would still be slightly under his gearing in 6th,OD which I spent most of the time in pulling 22k gross weight. If and- I repeat if- I need to I can always drop a gear. We each have our reasons but I can't see owning 4. 10's without an OD or other compensation unless you're a hotshot or local speed limits are 55.
------------------
01 2500 4x4,SB, QC, black sport, 5 speed, BFG All Terrains, leather, 3. 54, anti-spin, camper package,241HD,RBW 15k 5er hitch, tow package, tonneau, Xenon flares, Westin nerf bars, custom rubber flaps. Ordered 1/14/00, delivered 2/20/00- one day before 2000 mile 19k gross trip to Las Cruces- breakin it in right. 14000 miles. Amsoil synthetics and their oil bypass system, Greddy turbo timer. PS boost module on the way.
Bombed- gages and DD1's, former PMAX2
Toys- 84 coilsprung CJ-7 with 5. 2 magnum auto transmission, Go2Guy Engineering transfer case clocking adapter (Dana 300) and all the big dog jeep goodies.
Tige 2100i inboard ski boat w/ tower
30'Tahoe 5er with slide, soon to be modded with a rear deck and extra axle to haul the jeep!
------------------
01 2500 4x4,SB, QC, black sport, 5 speed, BFG All Terrains, leather, 3. 54, anti-spin, camper package,241HD,RBW 15k 5er hitch, tow package, tonneau, Xenon flares, Westin nerf bars, custom rubber flaps. Ordered 1/14/00, delivered 2/20/00- one day before 2000 mile 19k gross trip to Las Cruces- breakin it in right. 14000 miles. Amsoil synthetics and their oil bypass system, Greddy turbo timer. PS boost module on the way.
Bombed- gages and DD1's, former PMAX2
Toys- 84 coilsprung CJ-7 with 5. 2 magnum auto transmission, Go2Guy Engineering transfer case clocking adapter (Dana 300) and all the big dog jeep goodies.
Tige 2100i inboard ski boat w/ tower
30'Tahoe 5er with slide, soon to be modded with a rear deck and extra axle to haul the jeep!
What a loaded question. #ad
IMHO, I agree with most of the responses. Assumming you leave the truck stock, you'll see better fuel mileage with 3. 54's. I think the only time you'll actually see a 4. 10 out perform 3. 45s (on fuel mileage that is) is basically at max. tow rating (or maybe even exceeding max tow rating) and any towed weight above that. That's where the 4. 10s will have a fuel consumption advantage, among other advantages at that towed weight.
Definitely unloaded, your best mileage will be with 3. 54's. Anybody who thinks that you'll get better fuel mileage at 2,200 rpms at 65 mph, vs. 1,700 rpms at 65 mpg is just plain ole ..... well, I won't say it. Regardless of the fact that at 2,200 rpms the engine consumes fuel most efficiently, you'll still use MORE. Not only are you mechanically pulling more air/fuel through the engine, but as the revs go up the turbo makes more boost, even at steady state driving. So the added boost really puts the screw to the fuel mileage. That's my $0. 02 worth.
Those guys with the boost gauges know that even on level ground, the higher the rpm, the higher the boost will level off at. More boost, more fuel, more power. IMHO, lower rpms are more beneficial to a turbo-charged engine than a normally aspirated engine, for achieving better fuel economy, for the reasons as stated in the 1st 2 sentences of this paragraph.
------------------
Y2K 2500 Cummins ETC/DEE, SLT+, 4X4, Quad, LB, Intense Blue Sport, 3. 54 anti-spin, rear aux. springs (camper special), sliding rear window, all options except cab clearance lights including agate leather, totally stock, + a mpg increaser goodie. Since everybody else listed their toys, I will too.
1995 Kawasaki ZX6-R (For Sale)
1990 Toyota Celica
1983 Mazda RX-7 GSL (For sale)
#adIMHO, I agree with most of the responses. Assumming you leave the truck stock, you'll see better fuel mileage with 3. 54's. I think the only time you'll actually see a 4. 10 out perform 3. 45s (on fuel mileage that is) is basically at max. tow rating (or maybe even exceeding max tow rating) and any towed weight above that. That's where the 4. 10s will have a fuel consumption advantage, among other advantages at that towed weight.
Definitely unloaded, your best mileage will be with 3. 54's. Anybody who thinks that you'll get better fuel mileage at 2,200 rpms at 65 mph, vs. 1,700 rpms at 65 mpg is just plain ole ..... well, I won't say it. Regardless of the fact that at 2,200 rpms the engine consumes fuel most efficiently, you'll still use MORE. Not only are you mechanically pulling more air/fuel through the engine, but as the revs go up the turbo makes more boost, even at steady state driving. So the added boost really puts the screw to the fuel mileage. That's my $0. 02 worth.
Those guys with the boost gauges know that even on level ground, the higher the rpm, the higher the boost will level off at. More boost, more fuel, more power. IMHO, lower rpms are more beneficial to a turbo-charged engine than a normally aspirated engine, for achieving better fuel economy, for the reasons as stated in the 1st 2 sentences of this paragraph.
------------------
Y2K 2500 Cummins ETC/DEE, SLT+, 4X4, Quad, LB, Intense Blue Sport, 3. 54 anti-spin, rear aux. springs (camper special), sliding rear window, all options except cab clearance lights including agate leather, totally stock, + a mpg increaser goodie. Since everybody else listed their toys, I will too.
1995 Kawasaki ZX6-R (For Sale)
1990 Toyota Celica
1983 Mazda RX-7 GSL (For sale)
I just read issue 29 last night,and was surprised to read the article on gearing in the 24v section. THAT IS THE SAME DANG THING I'VE BEEN TRYING TO TELL THE GUYS ON THIS BOARD FOR THE PAST THREE MONTHS! The old saying holds true 'do as I say not as I do',please learn from my mistakes as this is my second 24v with 3. 54's.
I have mentioned before that the 3. 54's work great if you leave the stock tires on the truck,but most people rarely leave the stock size on a 4x4. I knew while I had my '99 that I was going to go with a bigger tire,so when I put in an order for a '00 6spd,I ordered 4. 10's(later cancelling the order due to 6spd restrictions). The truck I have now was bought off the lot with 3. 54's,but not because I wanted them. I later proved my own theory to myself when I put on 285/75/16's,that the 3. 54's were a mistake.
I don't want hear excuses from people saying "bomb the truck an you won't notice". BS! I have 295hp and 650tq and I can tell the difference,especially when trying to race someone while starting off in 2nd gear. I have also kept track of mileage differences on my last trip. I kept one fillup as close as I could to 1900rpm and another fillup as close as I could to 2100rpm... I saw a 1. 6mpg difference. Actually the boost was lower at higher speed because it required less 'work' for the engine to keep the truck going,keeping the motor in it's 'sweet spot'.
Once you put on bigger tires,get in line with the rest of us (complaining)24v 4x4 3. 54 owners
-Mike
------------------
'00 2500QC 4x4, 6spd, LB, 3. 54LS, SLT, Dark Garnet/Agate, Smittybilt nerfs, DD stageII, S/S braided fuel lines, Psycotty Air, 2wd low, 3"pipe bomb, Isspro pyro/boost, BFG 285/75at, Jacobs ebrake
I have mentioned before that the 3. 54's work great if you leave the stock tires on the truck,but most people rarely leave the stock size on a 4x4. I knew while I had my '99 that I was going to go with a bigger tire,so when I put in an order for a '00 6spd,I ordered 4. 10's(later cancelling the order due to 6spd restrictions). The truck I have now was bought off the lot with 3. 54's,but not because I wanted them. I later proved my own theory to myself when I put on 285/75/16's,that the 3. 54's were a mistake.
I don't want hear excuses from people saying "bomb the truck an you won't notice". BS! I have 295hp and 650tq and I can tell the difference,especially when trying to race someone while starting off in 2nd gear. I have also kept track of mileage differences on my last trip. I kept one fillup as close as I could to 1900rpm and another fillup as close as I could to 2100rpm... I saw a 1. 6mpg difference. Actually the boost was lower at higher speed because it required less 'work' for the engine to keep the truck going,keeping the motor in it's 'sweet spot'.
Once you put on bigger tires,get in line with the rest of us (complaining)24v 4x4 3. 54 owners
-Mike
------------------
'00 2500QC 4x4, 6spd, LB, 3. 54LS, SLT, Dark Garnet/Agate, Smittybilt nerfs, DD stageII, S/S braided fuel lines, Psycotty Air, 2wd low, 3"pipe bomb, Isspro pyro/boost, BFG 285/75at, Jacobs ebrake
Here are my real world mileage figures. Yellowstone trip drove 75 just under 2000 rpm air on 2365 miles,18. 5mpg. drove to Ohio,2057 miles 18. 7mpg,same speed air on. My truck drinks fuel over 2000rpm,overall I could not ask for a better gear. I have 285BFGs,4x4,3. 54,quad,longbox,275injectors. As far as bottom end power this thing will incinerate the tires,it tows #8000 fine. This is my third cummins,all 3. 54 and they all got best mileage below 2000.
It looks like the only thing that we can agree on is to disagree 
#ad
Or maybe that fuel mileage is subject to way to many variables for legitimate comparisons.
I drive a '00 2500 4x4 6spd w/4. 10's & 315/75R16 (34. 5" tall) tires. This is my second Cummins, second truck w/4. 10s. I run larger tires than stock and want max towing capacity. That said, I'm seriously considering an auxiallary overdrive in order to increase my cruising speed so I don't get run over on roads like I-5 thru the San Joaquin Valley.
My recommendation - 3. 54s if towing is not in the future. Larger tires & no towing = 3. 54s.
Brian
#adOr maybe that fuel mileage is subject to way to many variables for legitimate comparisons.
I drive a '00 2500 4x4 6spd w/4. 10's & 315/75R16 (34. 5" tall) tires. This is my second Cummins, second truck w/4. 10s. I run larger tires than stock and want max towing capacity. That said, I'm seriously considering an auxiallary overdrive in order to increase my cruising speed so I don't get run over on roads like I-5 thru the San Joaquin Valley.
My recommendation - 3. 54s if towing is not in the future. Larger tires & no towing = 3. 54s.
Brian
Depends on your load, driving speed and tire size. If using 265/75-16 tires in 6th gear you will be going 73 MPH with 3. 54 gears, and 63 MPH with 4. 10 gears both at 2000 RPM, which is peak efficency RPM for 24v engine.
For me, driving empty in Utah, highway driving is usually 70 to 75 MPH. With 4. 10 gears 75 MPH requires about 2400 RPM. That's a little high for continuous operation (although engine can handle it just fine).
I was pretty much set to order my truck with the 4. 10 gears until I test drove that setup (of course an empty truck). When I got onto the freeway and up to the speed everyone else was going (about 72 MPH) it just felt as if the truck needed to shift up another gear. Now if I was towing I would have probabily been in the right lane at 65 MPH and would have been comfortable with the RPMs. But as it was the gears didn't feel right to me.
Although I plan to tow a 10K trailer, most of my driving will be empty. I figure the 3. 54 is best for me. When towing, I will probabily have to downshift to 5th more often than if I had the 4. 10s, but I figure that's OK for my application.
By the way, if I was getting an automatic transmission I would have gotten the 4. 10 gears for sure. The overdrive gear on the autos is about 6% higher (0. 69 vs 0. 73) than the 6sp OD, and the auto needs all the help it can get.
------------------
Wait'n for my 2001 2500 QC, SB, 4x4, ETH 6-sp, 3. 54 LSD, SLT++ (everything but those lights on top of the roof), White over Silver, Tan leather. D1 status to ship 8/21.
For me, driving empty in Utah, highway driving is usually 70 to 75 MPH. With 4. 10 gears 75 MPH requires about 2400 RPM. That's a little high for continuous operation (although engine can handle it just fine).
I was pretty much set to order my truck with the 4. 10 gears until I test drove that setup (of course an empty truck). When I got onto the freeway and up to the speed everyone else was going (about 72 MPH) it just felt as if the truck needed to shift up another gear. Now if I was towing I would have probabily been in the right lane at 65 MPH and would have been comfortable with the RPMs. But as it was the gears didn't feel right to me.
Although I plan to tow a 10K trailer, most of my driving will be empty. I figure the 3. 54 is best for me. When towing, I will probabily have to downshift to 5th more often than if I had the 4. 10s, but I figure that's OK for my application.
By the way, if I was getting an automatic transmission I would have gotten the 4. 10 gears for sure. The overdrive gear on the autos is about 6% higher (0. 69 vs 0. 73) than the 6sp OD, and the auto needs all the help it can get.
------------------
Wait'n for my 2001 2500 QC, SB, 4x4, ETH 6-sp, 3. 54 LSD, SLT++ (everything but those lights on top of the roof), White over Silver, Tan leather. D1 status to ship 8/21.
With the 6 sp and 4. 10 cruising at 55 I'm running about 1800 RPMs (I say about because of the precise tach on these Rams). At 70 I'm turning 2200. I like the 4. 10 cause on the two lanes if I'm towing I don't want to go below 17/1800. I like the 4. 10 setup and running empty I'm getting a steady 20. 5 mpg doing the daily grind to work after turning 9000 mile on the odometer. Mileage has increased steadily since she was new (except when I got some low grade fuel).
------------------
2001 HO 6 spd 2500, 4. 10 LSD, Towing Package, Electric Brakes, EGT/Boost Gauges, Running Boards, Fog Lights, Real Backup Lights
------------------
2001 HO 6 spd 2500, 4. 10 LSD, Towing Package, Electric Brakes, EGT/Boost Gauges, Running Boards, Fog Lights, Real Backup Lights
As the others have said, if you aren't going to be towing heavy loads, then the 3. 54's are probably fine. If I were getting a new truck, I'd get the 6sp and 4. 10's because I'd be maxing out the GCWR on a regular basis (Lance camper and a car on a trailer too). I still think my '96 Auto needs 4. 10's particularly with my 225/70-19. 5 wheels (which I'd also move over to the new truck if I were to get one).
If you think you will tow a lot down the road, get the 4. 10's since it's better to spend $50 on the option now than $1000+ doing the conversion later. At least you sitll have more usable top end than a 12v with 4. 10's.
Rob
If you think you will tow a lot down the road, get the 4. 10's since it's better to spend $50 on the option now than $1000+ doing the conversion later. At least you sitll have more usable top end than a 12v with 4. 10's.
Rob
- Status
Issue 128 – Digital Version
Digital Magazines
FREE!
TDR Test Drive - Digital Edition
Renew
Subscribe
Gift Subscriptions
Back Issues
Subscription Status
Address Change Form
Buyer's Guides
Ram Diagnostic Trouble Codes
The Perfect Collection
The Perfect Collection Vol. II
TSB Updates
Dodge/Cummins Historical Overview
Cameron Collection
What Makes Us Tick?
Product Showcase
Advertising
Turbo Diesel Register
Issue 128 – Digital Version
Digital Magazines
FREE!
TDR Test Drive - Digital Edition
Renew
Subscribe
Gift Subscriptions
Back Issues
Subscription Status
Address Change Form
Buyer's Guides
Ram Diagnostic Trouble Codes
The Perfect Collection
The Perfect Collection Vol. II
TSB Updates
Dodge/Cummins Historical Overview
Cameron Collection
What Makes Us Tick?
Product Showcase
Advertising
