4:10 and auto RPM's

[pwr2tow]

Hi all need your input, I really need information from those with 4:10 gears and auto transmission, what are your engine RPM's in OD for 65MPH and 70MPH. I am thinking about changeing out mine from 3:54 to 4:10 for better towing performance and better fuel mileage while towing. I know the 4:10's might hurt my mileage slightly unloaded but my way of thinking is that with the 3:54 gears towing i'am not in the RPM range for optimum performance hence then iam putting my foot in the throttle more to try and make HP but the RPM's are not there for the amout of HP i need so am wasteing fuel trying to produce HP. The other thing is that according to cummins BSFC charts i would be better off with 4:10 at 2200 RPM's than be lugging along at 1800 RPM's with 3:54's trying to make HP. I triple trailer everything in my signature and need all the help i can get. I need the RPM information to make a decision on the 4:10 gears. Thanks to all how respond. Regards, Ron

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1999, 3500, 6x6, slt, auto, 3. 54, Qd cab, ISB cummins, towing 2001 26RKSS Tahoe 5th wheel, 1999 120hp 1800 bayliner.

 

[big barney]

I don't know anything about the 4. 10 gear. I have the same year truck as you. I installed a VA and the difference between 1500 and 2000 rpms is like night and day. It really makes the power in that rpm range.

 

[Royal]

You should consider a aux. unit ,like Gear-vendor,then you can tow in 3rd& OD,and when empty run OD + OD and you will have the best in both worlds. My freind does it and says itsthe only way to go.

 

[Barry]

My 6spd/4:10 turns 2125 @65mph. Your automatic will be turning slighly less. (maybe 25 rpm). This is assuming you are running 235 tires... ... ..... I had a 2000/3500 6spd. with the 3:54s and it would not pull the hat of your head. I kept it 7 months and sold it. My 2001/2500 6spd. 4:10s is the hardest pulling truck I have ever owned.

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2001 2500 QC, ETH/DEE,4:10s, LSD, EZ with elbow(26. 5PSI) Boost/Pyro Guages, 4" Turbo back, BD Brake,Mag-Hytec Cover, Kleen Wheels, Energy Release, 70 gal. fuel, 20K Reese. 25,000 Miles on 01/30/01(RV Dealer)

 

[MikeR]

I think there is a speed comparison chart on Dave Fritz's website. Jump over and take a look.

-Mike

 

[Big K]

I ordered our '99 w/4:10 after researching the power curve of the engine, and knowing that I wanted to increase tire size. We are currently running Goodyear 305's that measure very close to 32" dia. This decreases our numerical gear ratio to somewhere near 3. 8+/-. OD rpm is about 2000 @ 65mph. I am very happy with this gearing combination, but I don't believe that I would like a tire smaller than 285 or so. As suggested, there may be more economical/versatile ways of improving your towing performance.

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'90 W-350 5-sp 230K
'99 2500 QC 4x4 AUTO 4:10
EDK

 

[csutton7]

i've got 35" tires w/4:10 gears and I'm fairly sure I'm at 2000rpm at 60(my speedo may be off as I've not calibrated it, but I think it's close as I'm not jetting by people at 60 like I was before with 3:54 gears)--it's a great combo----chris

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chris sutton
1999 2500 qcab longbed 4x4 red sport w/ all the options 'cept plow pkg, 4:10 detroit locker in rear & front ARB,
5" skyjacker lift w/ 35" BFG mud terrains on 16. 5x9. 75 Weld rims, black smittybilt nerf bars, black 3 pc. bug persuader,
black lumber rack, camel leather int. w/ mb quartz spkrs and 8" sub, power edge EZ, DTT vb & tc, mag hy-tec transmission pan,
red magview diff covers & coming soon: 275 injectors, red L&L ladder bars, turbo temp monitor & guages on "A" pillar

 

[NDRamrod]

I read on here before that there is a 300rpm jump in od when you go to 4:10's. I know I am like you 70 at17-1800 rpm I don't recall exactly. but the rpm jump would put you in the money for rpm range I think. But like somebody said DC does not want you to tow in OD, but everyone does.

 

[NDRamrod]

sig

 

[NDRamrod]

sig

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2001 bright white qc, sb, 4x4,auto,3. 54s, slt laramie, camper group,trailer group,6spkr infinity cd, travel convenience package, cloth seats in agate, stainless running boards (Wifes orders), stainless wheel opening trim, stianless steel tube box rails, and soft roll access cover(toneau cover), 5th wheel hitch( stock trailer-flatbed , K&N Air filter, 265/16s on factory aluminum wheels.

 

[Guest00]

Been there, done that!!

go to https://www.turbodieselregister.com/ubb//Forum4/HTML/003910.html

All the info you are looking for!!!!!

I have ordered a Gear Vendors OD unit.

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2K, 2500, Quad, 4x4, 3:54LSD, A/T, reese 15k 5th slider, EASLEY BULL BAR, WESTIN NERFS, TA's, 9000's, stealth DD2's, DD Boost & elbow, ISSPRO pyro & boost, Turbo Lifesaver, JARDINE 4", DTT VB,TC,TC SAVER and AUX COOLER, PAC BRAKE, MAG HYTECH TP& DC, onboard. Taylor Wing and Gear Vendors on order
pullee #1 26' Arctic Fox 5th
#2 22' car hauler w/ 76 Pinto 392cid or 68 Cyclone GT Cobra Jet FB
NRA-LIFE, VFW-LIFE, SoCSA-LIFE, SASS

 

[NDRamrod]

Just got done reading a link in hear that a guy put on a US gear OD. Said the other mounts inbetween the transmission and transfer. and the us mounts on the rear of transfer case. Thus that one will not smoke transmission if it blows??

 

[Jar Head]

2100 at 60 MPH
2200 at 79 MPH

I'm very happy with the 4. 10. With the 245 tires, the truck accelerates very quickly and tows in the mountains with aplomb.


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Made in Mexico: 2001 Dodge Ram 2500 HD 4x4, LWB, Regular Cab ST, ETC, Auto, 4. 10 LSD, Camper Package, Trailer Package, 100% Stock.

 

[Jar Head]

That's 2200 at 70 people.

 

[pwr2tow]

Thanks for the responses guys, still do not know what to do yet so i will keep looking for information before i do anything. I am leaning more towards installing DTT TC and valve body along with DD true torque enhancer module. The price would be about the same BOMB or 4:10's, not enough money this year for both. maybe the gearvendor OD what to do so many options. It will be awhile before i do anything but spring is comeing and i want this done before then. I had my truck reflashed awhile back and have not been able to tow with it yet but monday planning on a 200 mile trip to have 5th wheel raised a few inches. when i get back i will post my results. My truck has shown some in fuel mileage improvements even for winter since reflash but iam not getting my hopes up yet. JFYI my truck has 24,000 miles and i use #2 fuel year around with additive year around. I love this truck and would not get rid of her for any thing (well just about anything), she pulls better and rides nicer and the feeling of driveing around in that big one ton just about gives me wood,wwooooohhhh just about got off track here, but i wish i had better fuel mileage. Thanks again for the responses. Regards, Ron

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1999, 3500, 6x6, slt, auto, 3. 54, Qd cab, ISB cummins, towing 2001 26RKSS Tahoe 5th wheel, 1999 120hp 1800 bayliner.

 

[RobbyRam]

My 4:10 Auto runs exactly 63 mph at 2000rpm's.

At 65 I'm about 2100. At 100mph I'm . . oops!

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Bob in Sacramento, Y2K Black 3500 ISB 4x4 4:10 LSD,Auto,QC,SLT Laramie, Slightly BOMBED LB, Polished Stull Billet Grill & Fog inserts, Chrome Smitty-Built Step Rails, Mopar Chrome-Tipped Mud Flaps, A-Pillar mounted West-Tach Turbo/Pyro/Trans Temp gauges,Rancho 9000's set at '1',Diamond Plated Tool Box, OEM U. R. Bedliner + other stuff.
Fact:The First Fords' had 'DODGE' Engines! The new PSD's need them!

 

[CaptainEric]

Well call me crazy but I went with the US Gear underdrive. Numerically it works out to a 4. 42:1 ratio when set to low range. This gets me 65 mph at about 2250 RPM in OD. A great side benefit is the gear reduction below 1st and reverse. When manuvering my 5th wheel in low range it has reduced my trans temp by 20 degrees or more. So far no problems towing in OD. It is a little rough when shifting but, there are no clutches involved either. When towing I usually just set it to low range and enjoy the drive.

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1998-1/2 2500 Quad Cab, ISB, Auto, 3. 54 LSD, LWB, RBW 15K 5th wheel hitch, Rhino Liner, US Gear Dual Range underdrive,Weston Smirf bars, Bilstein shocks, AMSOIL bypass filer, synthetic engine oil and differential lube, Mag Hytec diff cover, Turbo Diesel Life Saver, Trans. temp guage, Boost & EGT dual guage, Stone Guard headlight protectors, 5" monster chrome exhaust tip, Better Built diamond plate tool box & bed rail covers, louvered 5th wheel tail gate, custom cummins stainless steel rocker panels.

1998 Alfa Double Slide 5th Wheel RV - See Readers Rigs page 6 for pictures.

 

[edgar2]

To Ronsram- I have a 2001 2500 QC auto with the 410 rear end and trailer tow pkg. and am pulling a 10500lb. King of the Road 5th wheel. I lock out the OD and at 3000rpm, I'm going 65-67mph. In OD on a short level stretch at that speed the rpm's dropped to 2400. From Texas to Ariz. and back last month we averaged right at 7. 9 mpg. The engine had plenty of pep left at 3000.

 

[Homicide]

Ronsram 1999;

You may really want to keep your 3. 54s. I swapped out my 4. 10s for 3. 54s because of the hi RPM cruising on interstates and for towing reasons.

On trips from SF to Los Angeles, 2000 rpm would put me at 60 mph; 2400 around 70 mph, which was too much humming for my ears.

Towing up a long grade, I dropped out of O/D and was only making about 50 mph at the 2200-2300 rpm mark, and the truck made way too much noise trying to keep speed at 55 w/o O/D in 4. 10 gears.

Now with 3. 54s I'm happy going 80 around 22-2300 rpm.

Fuel economy while driving in the 60-65 range was about . 2 better with the 4. 10 gears, but that was when the truck was still being broken in at 10k miles.

The Gear Vendor splitter sounds like a nice fix to your problems because of the different gear choices or keep you 3. 54s and slightly BOMB with an EZ box as I did today... a lot cheaper than gears.

I have 285/75 tires at 33 inch diameter with my 3. 54 and love the set up.

 

[Gryph]

Hi all , this is my first post. Have a question on towing in OD . Is this hard on the transmission or engine ? The first thing i've learned here is that i need gauges - and they will be installed before i tow in the spring. I have the automatic trans and a 3. 55 diferential , and have only taken out the OD on long grades .