2nd Gen Non-Engine/Transmission 3.54 gears vs 4.10?

[THenningsen]

Is there that big of a difference? What kind of fuel milage is sacrificed by going with 4. 10s? Any other drawbacks besides fuel economy?

 

[hammersley]

Huge fuel penalty.....

In the 10-15% difference at same speed... ... unloaded - and unless you're towing heavy - not needed - also - with those extra RPM's - you will wear your engine out faster - there are only so many Revs/Engine - no matter who makes em - use em up fast or slow - your choice.....

 

[hammersley]

Huge fuel penalty.....

sorry - double post - eliminated the 2nd - web site was SLOWWWWWWWWWWW

 

[rweis]

If you tow heavy you are right in the most efficient range of the engine ~ 2000 rpm. If you tow heavy, your turbo is spooled up better because of the faster engine speed. I think the strain on the whole drive train is less because you are 4. 10 the ring gear and pinion instead of 3. 54 (my opinion).



I had 3. 54 and went to 4. 10. Cost ~ $2000 local machinest did the work.



Auto transmission works better, turbo works better, easier to drive with load, wife can now drive loaded because she is not going in / out of O/D based on upcomming terrain and rpm. Boost is cooler because more rpm.



It might take more rpms (I am not sure I buy you only have a certain # of rpms), but I would rather rebuild the engine (if that is true) than fight it for 500,000 miles.



My driving style is slow and steady. It might not be for someone that wants to run 80 mph mile after mile, I run 63 mph (2000 rpm) in the right lane and do not give a flip what anybody thinks about my speed, I optimize the machine, period.



Bob Weis

 

[DonTX]

Well, I disagree with that. I looked long and hard to get me a 3. 54 and am very happy I did.

I get great mileage empty or towing, the transmission takes care of gearing, that is what an automatic is for. I generally cruise at 70 at 1750 rpm. Some people love to cruise along with the tach at redline, not me, fuel prices make me glad I have the 3. 54. Empty my fuel mileage is at the 23-24 range. .

 

[jkern]

3. 54's here. at the stock level there isn't really a clear winner... i think. if you are going to put 35 inch tires or larger on the truck then definetly go with the 4. 10's cause the big tires will effectively gear you up.

 

[EKlem]

Like the above posts have said, it depends on how you use the truck. You can tow moderate loads just fine with the 3. 54 but you will have to downshift more often. If you are going to tow real heavy a lot, 4. 10's are the way to go.

Regarding how long parts will last, there is less strain with the 4. 10's which will really help your transmission. Running more rpms can wear out some components faster but I believe that is negligeable if you are actually running a loaded truck because of the benefits you are getting. With the marine engines that I work on, my observation has been that their life span is more closely related to the amount of fuel they have burned than the rpm.

For fuel economy, again the choice depends on how you use it. If your truck rarely exceeds 55mph, 4. 10's will give you better economy. They are better for fuel economy except on the top end where you run out of gears in your transmission. So if you are running empty on the highway a lot, you will get better economy with the 3. 54's but if you tow a lot or are in town a lot, 4. 10's are better. A lot of people are afraid that higher rpms will destroy fuel economy but they forget that lugging their engine is just as bad for economy and does more damage.

 

[Gene Arnold]

I have a 4:10, not by choice, but because I bought the truck used and that is what it had. That being said, I'm happy with mine. I'm not driving it much this winter due to the fuel prices but I normally get 18-20 around town and around 14. 5 most of the time when I pull the Airstream (8500#). 2100 rpm is 62 mph on mine.



Gene

 

[SS]

I have 36" tires and I often find myself looking for 7th gear.



I ordered the 4. 10's knowing I was going with a bigger tire, but if I had it to do over I would get the 3. 54. It's easy to add more power, but adding more gears is difficult. With the lift, tires, bumper, and a heavy foot I get around 17 mpg.



I don't tow heavy often and usually run pretty fast - I can see how guys that use their trucks differently have other needs.

 

[hammersley]

At a steady 55

"For fuel economy, again the choice depends on how you use it. If your truck rarely exceeds 55mph, 4. 10's will give you better economy. "



I can get 26+ - all the time - there is NO way you can get that with 4. 10's

 

[DonTX]

True with a 5 speed, but of course it is impossible to lug an automatic.

[QUOTE A lot of people are afraid that higher rpms will destroy fuel economy but they forget that lugging their engine is just as bad for economy and does more damage. [/QUOTE]

 

[JLandry]

THenningson,



I recently had the axle ratio on my 47RE auto transmission equipped 2001 changed from 3. 54:1 to 4. 10:1 at Randy's Ring & Pinion in Everett, WA to make towing a heavy (and draggy) travel trailer more pleasurable in hilly or mountainous terrain.



Without the travel trailer and the 3. 54:1 axle ratio, my truck averaged about 21mpg with mostly highway driving. On one trip last summer in central Oregon, I averaged 24 mpg. The 3. 54 gears were great under almost all driving conditions up to including medium loads, but not so great with the travel trailer.



With the heavy travel trailer in tow at 60mph, the engine rpm in 4th gear was just too low for anything but towing over level terrain without a strong headwind. The slightest incline forced downshifting to 3rd to keep the EGT's reasonable. On one particular trip where I towed the travel trailer through the Columbia River Gorge, I had to keep the truck in 3rd for hours due to a strong headwind. Towing in 3rd gear at 55 to 60mph with that nasty headwind, the fuel economy was around 10mpg!



My truck now has about 700 miles on the odometer since changing the axle ratio to 4. 10:1. I've recorded about a 1/4 to 1/2mpg drop in fuel economy when operating without the travel trailer. I haven't yet taken a trip with the travel trailer since the gear change, but I anticipate the fuel economy may actually be better than before.



The truck also has noticeably more "pep" with the 4. 10:1 axle ratio.



Regards,



JAL

 

[EKlem]

"For fuel economy, again the choice depends on how you use it. If your truck rarely exceeds 55mph, 4. 10's will give you better economy. "



I can get 26+ - all the time - there is NO way you can get that with 4. 10's

I stand by my statement. The reason I say as long as you keep the speed below 55mph, is that with a 4. 10, you will run out of gearing for economy at a speed greater than that. By running a 4. 10, you essentially have more gearing options at slower speeds so an experienced driver can run the engine more efficiently. Up to about 55mph, running in 5th gear with a 4. 10, your rpms will be in the correct range. Faster than that and you need more gears so a 3. 54 would be better.



Remember, gearing isn't as big a factor(excluding extreme mismatches) as wind resistance. If you want better mileage, the best thing you can do is slow down.

 

[NoSeeUm]

Take a look at this Gears Website. It is user friendly and very useful.



I Used:

NV4500 - Manual transmission

NV241 - Transfer Case

285/R16 - Tire Size



Comparing 3. 54 vs 4. 10



Looks like you gain roughly 237 rpm with the 4. 10's at 55 mph. But notice that 3. 54's in 4th gear vs 4. 10's in 5th gear where the rpm difference is 262 rpm. IMO that means 3. 54's pull better in 4th vice the 4. 10s in 5th plus you still get another gear when empty.



Dropping to a 265 tire and keeping the 3. 54's nets a 154 rpm rise, or basically splitting the difference when going from 3. 54's to 4. 10's. But you lose some weight carrying capacity with the smaller tires.



You could probably say close to the same thing about the NV5600. But of course, the NV5600 will always pull better in general due to the large gap between 3rd to 4th of the NV4500.



So if it were me. If I pulled allot of weight mostly on windy / hilly terrain or allot of starts and stops and / or lived in the Mountains. Then I would chose 4. 10s. Same conditions on State Highways or the Interstate for moderately flat countryside then I would chose 3. 54's.



Jim

 

[Clinton]

Seems like this has been an age-old TDR debate. I have a 4. 10, 4x4, auto-equipped rig. I run 255/85 Toyos to gear it up a bit. I live in the mountains and I agree the 4. 10s help the auto work a little better. I can get 21 mpg if I go easy on the throttle and about 18 mpg when I get in a hurry. Nothing wrecks my fuel economy like a tall load and poor wind resistance. I've noted fellow members mileage for years and I do not think I would see considerably better mileage by gearing up to the 3. 54s. If I thought I would gain even 10% better mileage, I would've swapped gears by now. The only people I've noticed that get crazy-good mileage have 2wd trucks (like you). Whatever your axle gear, you should be in pretty good shape for choosing engine rpm with your 6 speed transmission. Like everybody else has said: it comes down to how you use your truck. You want to run fast empty? Your 3. 54s should serve you well. Tow heavy and not too concerned about speed? 4. 10s are good for that, but if you investigate the price of swapping gears, you may find that it is an expensive proposition. I don't know about 2wd pricing, but I think you still have to have a new carrier to bolt that 4. 10 ring gear to.



I'm not so sure about the comment regarding engine life being a function of total revolutions. Sounds a little simplified to me.