Gears & aux transmission

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Am thinking about a new truck. Need some educated opinions as to proper gear ratio. Should I go 3. 54 with an under-drive or 4. 10 with an over-drive. Will be ETH/6 speed. I tow a 15k 5er in the mountains about 15 times a year.

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99 2500 QC 4X4 5sp / made in Mexico /
3. 54LSD 285 75X16 AR Atlas / Hadley airhorns / DDIII - 4in exhaust, turbo back - HD clutch / ISSPRO guages / 33' Hitchhiker triple slide (can you say HEAVY)

 

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For pulling that much weight, I'd get the 4. 10. If you decide you'd like faster gearing you can put taller tires on later. The 4. 10 will put your gears closer together too! Craig

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97 3/4Ton, 2WD, 5SP, #11 Plate, 14 Housing, AF942M Air filter, Gutted Cat, 4"From Turbo, Airlift, Shortened Frame, Custom Bed, HEY FORDBOY POWERSTROKE THIS!

 

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If you can say heavy, you should say 4. 10's.

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'01 2500 QC SLT (white/mist gray), 4x2, SWB, Cummins, Auto, 3. 54 LSD, Tow Package, 4wABS, Luverne SS Side Entry Steps, Truck Trunk, Reese 18K Classic, Tekonsha EnvoySV, Pioneer DEH-P47DH, Kenwood TM-733A. 24' SunnyBrook 5er with solar. Ram Ham: N0MEU

 

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I have an 01 5 speed with 3. 54 gearing. I do a fair bit of towing and to get the engine into the proper rpm range I would have to do alot of speeding. Suggest if you want to use top gear towing go with the 4. 10. Otherwise you will either risk tickets or spend alot of time in 5th (4th for me).

 

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NO FRIGGIN WAY!!!! The ETH has so much torque, you will yank 15k throught the mountains just fine with the 3. 54!! Think about this: a diesel is designed to pull at "low" revs. Why would you gear the vehicle to run at high revs? Besides, the truck has 6 gears to choose from... if it lugs a hill, downshift! duh!

 

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Seems like alot of folks have regreted going with the 4. 10. 15k would be a light load for my 3500 with 3. 54. With a normal 28k load I just have to run the rpms up to red line before shifting,with 15k you won't even need to do that. You'll like the 3. 54 a lot better when when you're running empty.

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95' 25004X4,AT,Driftwood,Banks,Warn fender flairs and running boards(Play truck)95 3500,5 speed,driftwood,Banks&phscotty,34,000 GVW apple and tractor hauler(work truck)

 

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2500rpm peak HP IS low rpm compared to 4200rpm for a 454 gasser at peak HP. I had a '95 with 3. 54 and now a '98 with 4. 10 and 5spd. The 4. 10s better match the power band for towing. From 60mph/2100rpm to 70mph/2500rpm, I'm in the horsepower. 1750rpm with the 3. 54 gave me better mpg towing but the difference in power with the 4. 10s in O/D is well worth the difference to me. After I got used to hearing the higher rpms at 70, I now run 70/2500rpm all day with good boost, lower egt and excellent response. And 14% more torque to the road with 14% less stress to the driveline through gearing. More fuel equals more power and the safest and easiest way to add more fuel is with higher rpms. Just my ever so humble been there and done that opinion. I know peak torque is at 1600rpm where efficiency is. Peak HP is at 2500-2600rpm and that's wear the power is.

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98 2500 CC 4X2 12v 5spd 4. 10
97 Dodge Stratus 150HP
92 Harley Fatboy, Dynojet fuel management, Supertrapp 2-1

 

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maybe I didn't word this right. I am going to add an auxillary transmission. The question is go with 3. 54 and an under-drive aux or go with 4. 10 and an over-drive aux. I know what the 3. 54 will do now (see my signature). I curious because of the auxillary trans.

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99 2500 QC 4X4 5sp / made in Mexico /
3. 54LSD 285 75X16 AR Atlas / Hadley airhorns / DDIII - 4in exhaust, turbo back - HD clutch / ISSPRO guages / 33' Hitchhiker triple slide (can you say HEAVY)

 

[Archive]

Rick, dont forget... if you get a NEW truck with the 6 speed, it will have a lot more power than what you have now. Once again, get the 3. 54, then do the US Gear overdrive! That would be a KILLER combination! 15k is not a big deal, really... i pulled a race car trailer with 3-axles with my 2wd 2500 and always scaled over 24k... . i had the 5 spd. with 3. 54 and did some mild bombing to about 250hp. At 70mph with the air on, I was turning just over 2000rpm and got 15. 2mpg. Your 'new' truck could run up the hills in either 4th or 5th overdrive, then when empty, you could either run 135mph or get wonderful mileage! Dont forget, you pull with torque, not horse power... so look at the engine graph to tell you where you want your RPMs. I recommend the US Gear brand because you can leave the unit in overdrive for each gear VS. the Vendors which will not.

[This message has been edited by BCFAST (edited 09-06-2000). ]

 

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You are confirming that you are definately getting an auxillary transmission to compliment your 6 spd. If you feel your current setup has the right top end ratio for your weight hills and speeds you like to travel- stick with it. The tough part is deciding to go with a combo you have not run before.

My buddy's 3500 QC non- eth 6 speed 4x4 has tires about an inch shorter than yours. He had 3. 54's and the gear vendors OD unit. He swapped for the 4. 10 as he had the OD vs. the UD- but not sure if he ever even ran the 3. 54 with OD.

Anyways- he's got the full banks kit and most often grosses 23. 5 K- your ballpark. I drove this setup to Farmington NM and back to AR (Route 40, 25, 44)and spent most of the time in 6th OD in excess of posted speed limits. If you're planning to bomb again I know this setup works well. I gross around 19. 5 and wish my 5th gear was a little taller (Bigger tires next time)and I'm only lightly bombed.

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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!

 

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While deciding if I was going to get a new truck (which would be a 6sp), I decided that 4. 10's plus an overdrive box was the way to go (instead of 3. 54s and underdrive). I have an Excel spreadsheet that somebody sent me a while back that I used to compare RPMs and MPH and stuff to figure out what would work best.

If anybody wants a copy, I stuck it on my website at http://www.f-body.org/rob/SpeedChart. zip.

Rob