2nd Gen Non-Engine/Transmission Trade your 3.54 for my 4.10 gears?

[nwilliams98]

Hi everyone,

I have a 97 2500 un-bombed 4X4 CTD, 37000 miles, manual 4. 10 gears. I would like to swap gears with someone. I don't tow often so I don't need the 4. 10 gears. I would like to get the better gas mileage of the 3. 54.



I've heard that it is expensive to just buy the parts so if anyone wants to trade let me know. Or, if anyone knows how to pull this off inexpensively I'd really love to know.



Let me know. I'm in Monterey CA.

Thanks,

Nate

-- email address removed --

 

[DEZLPWR]

I'd trade you but....

you have a Dana 70 right? I have a Dana 80... .

 

[thekidfan]

Do you have an auto transmission or a 5spd? The auto has the 70, 5spd. the 80. I might be interested. LMK Jeff

 

[Hummin Cummins]

I'd love to trade but you're so far away:{

 

[willyslover]

with a little over 6000 avg. miles per year why bother. . unless it's new to you

 

[nwilliams98]

Sorry,

I neglected to mention that it is a 5spd manual which I think makes it a DANA 80. The truck is new to me and will get a lot more miles on it now than 6000 per year. Let me know if this is what you are looking for.

Nate

 

[LSMITH]

You are too far for one, and I have the 70 rear for two. I can keep hoping someone closer with an auto will want to swap

 

[TowPro]

My 98 has 3:55 gears, 245/75/16 stock tires, and a manual

65mph = 2000 rpm



My 2002 has 4:10 gears, 235/85/16 stock tires and a auto trans.

65mph - 2000 rpm.



It may be cheeper to just go out and buy different size tires, then have the dealer re-program the computer to display the correct speed.



Plus the 235/85 sell for less money.

Originally posted by nwilliams98

Hi everyone,

I have a 97 2500 un-bombed 4X4 CTD, 37000 miles, manual 4. 10 gears. I would like to swap gears with someone. I don't tow often so I don't need the 4. 10 gears. I would like to get the better gas mileage of the 3. 54.



I've heard that it is expensive to just buy the parts so if anyone wants to trade let me know. Or, if anyone knows how to pull this off inexpensively I'd really love to know.



Let me know. I'm in Monterey CA.

Thanks,

Nate

-- email address removed --

 

[lmills]

I am in MD looking for a trader. I have the 4. 10's and auto. I could provide a shop and help probably also. What else would need to be done if you were to switch gears? As in transmission shift points and the odometer?

 

[nwilliams98]

I'm running 265-75-16's right now and I'm still turning 2250 or slightly more at 65mph.



I'm looking to switch to 255-85-16 which will only drop me 100 rpm. I need the gear change to get into a more efficient rpm without adding the rotational inertia of huge tires.



Thanks to those that have replied.

 

[DEZLPWR]

Is Monterey in northern or southern CA? I am up near Seattle... .

 

[lmills]

I am currently running 285/75's on my truck with the 4. 10's. I turn 2,000 RPM's at 65 with that combo.

 

[nwilliams98]

Monterey is about 100 miles south of San Francisco. The locals call it Nor Cal.



I'm from Spokane so I if I don't get any local takers maybe I'll look you up when I head up there in June or July.

 

[nwilliams98]

Imills,

That is wierd because I'm so much higher than you. Do you have your speedo recalibrated? I don't know if the previous owner did when he went from 245 to 265. Does anyone know what rpm I should be at for 65mph with 265-75-16 and 4. 10 gears?



255-85-16 should be higher than the 285-75-16 so maybe I could go even lower than 2000?

 

[DEZLPWR]

I have heard that the cost of the gears themselves is minimal vs. the amount of labor $$ it costs to swap them out.....

Have you spoken with a gear installation shop to confirm or deny this? Might be a good idea.

 

[TowPro]

Using This Caculator I came up with the following tire diameters

245/75 = 30. 5"

235/85 = 31. 7"

265/75 = 31. 6"

255/85 = 33. 1"



Now the 5 speed has a . 75 gear ratio in 5th.

The auto has a . 69 gear ratio in 4th.



Using This Caculator I came up with the following speeds at 2000 RPM for the 5 speed.

Tire size - 4:10 ratio - 3. 55 ratio

245/75 = 58. 90 mph 68. 19 mph

235/85 = 61. 21 mph 70. 87 mph

265/75 = 61. 02 mph 70. 65 mph

255/85 = 63. 92 mph 74. 00 mph



Just to check the math, I ran my auto's . 69 ratio and came up with 66. 54 which is real close to 65mph. which is what I am seeing.

 

[lmills]

I never had the speedo re-calibrated after going from 245->285's. I figured out that mine was off by10-11% by watching the mile markers between home and work. It is a 40 mile highway run and my odometer was showing 36 miles. At first I thought that maybe the markers were off. So I paced my truck with 2 different other trucks that were bone stock. Both people had Nextel two ways so we could keep in touch. When my speedo showed 30 their's showed 33. At 59 on mine theirs showed 65. That was enoguh to convince me. I just subtract 10% from my speed to compensate. Besides it helps me on the warranty.

 

[nwilliams98]

Thanks for the help guys. I think my speedo is off by a hair. After looking at the calculations I don't think that I am ever going to get into the most efficient RPM range with tire size changes alone. So, for now I'll keep looking for a gear swap. I heard somebody else got the swap done for $200 earlier this year in Canada so I'm hoping its a similar price down here. Keep the input coming!

 

[CFAR]

"I'm running 265-75-16's right now and I'm still turning 2250 or slightly more at 65mph. "



Sounds like your speedo and tach are both off a wee bit.



the 265's are an optional tire size for your truck as are 245's

mine with 3. 54's does about 1850 rpm or so.



IMO I don't think you should be running at 2250 at 65mph.





Woody

 

[thekidfan]

cost

$200 for the rear end plus a little more at most shops for the front end labor only.