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Gear ratio

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Trailer Not Connected on new truck

  • Brushy Creek Ranch
  • Replies: 12
mwilson

Ozy and Steffi travel to Lapland...

  • mwilson
  • Replies: 11
I like my 3:73 as well, until I tow in Comifornia. 55mph for "autos with trailers and trucks" keeps the RPM's low causing me to hunt for the sweet spot with my G56.
 
May just be an old school way of thinking (and too many years towing with a 47RE) but I prefer not to tow much above 60% of the trucks capacity in 6th over long distances anyhow. The split between direct (4th) and 5th gear (.81) is the closest of any transmission in the HD pick up segment and is where the transmission will be the happiest.
I may be just prude, but if that is your only complaint of the truck I'd just lock out 6th and call it a day. Regearing would also be cheaper than taking a hit on a new rig.
Of course, if you want a new one just because then there really doesn't need to be a "reason" :D
 
These 13 and newer trucks are ALL SAE rated to do the job RAM says they can. I would have destroyed this 15 towing 33 to 35K combined with ZERO issues towing in 6th and also my 11 towing 29K WAY over it's ratings towing on flat ground in 6th but later just locked in 5th.
 
Towing in .77 ratio 5th gear at 60 with 3:42 gears is probably better for the transmission than towing in .63 ratio 6th gear at 60 with 4.10 gears.

I tow a 16K 5er with a combined weight of 24,500 and would not trade my 3.42 for anything lower. In 38K miles and 2.5 years have never had stutter or other issues, besides the lazy cruise control towing over 6,000 feet alt.

To OP, I guest I understand the duallie is because of the truck camper. My Aisin with 3.42 shifts gears by truck speed in TH. 55 it shifts from 4th to 5th and will not shift to 6th until 65 MPH. I lock out 6th for towing only because of down hills and the exhaust brake operation.
 
Cummins12V98 said:
Your example both will be turning close to 1,750 rpm's, why would the 3.42's in 5th be better for the trans?
Click to expand...

Power is applied to a smaller output side gear in 6th most likely. 3.42 will also have a larger pinion gear, right?

If you are going give away a gear you do not need, why give away 6th for cruising. With 4.10's and a mid size load you are giving away the Aisin 1st gear, as an un-needed gear.

I would much rather have the cruising gear available than a un-needed low gear.

This all goes to the heart of how the latest 6.7's are tuned for low RPMs.
 
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Speaking from a strictly transmission view point it will always be more efficient and less parasitic loss on the unit towing in direct or as close as possible. It's a matter of transferring power directly through the main vs transferring power through a countershaft. The taller the OD gearing the more efficiency lost, yes I believe both transmissions are engineered well enough to tow their published ratings in OD and my above statement is likely overly conservative, but the worst that's gonna happen is I'll burn a little more fuel. I'm ok with when I notice the truck actually working easier.
 
Just some useless info here. When in TH/EB with AISIN and 4.10's my truck under normal acceleration shifts at 2,000 drops to 1,600 and so on. 1,500 or so drops a gear so it's always going to accelerate with NO lugging.
 
Cummins12V98 said:
Just some useless info here. When in TH/EB with AISIN and 4.10's my truck under normal acceleration shifts at 2,000 drops to 1,600 and so on. 1,500 or so drops a gear so it's always going to accelerate with NO lugging.
Click to expand...
What RPM when empty, as an example 50MPH T/H off and Aisin in Drive cruising on level ground?
 
Well, I guess I will throw my two cents in! I bought my 2017 DRW Mega-Cab 4x4 with the Aisin and 3.73's last April. I live in Monument CO which sits between Denver and Colorado Springs at about 7300 feet of elevation. My truck now has a touch over 30,000 miles, probably 75% or better towing our 15,000 39 foot fifth wheel...we are now "full timers". Our travels take us out to CA to Sacremento and Napa Valley, down to Bakersfield and Blythe, over to AZ to Phoenix and Tucson, back up to Monument, over to Tulsa and as I write this, I am sitting in an RV park in Panama City, Florida. I write the above, just to give some background for my following thoughts on what constitutes the "ideal" gear ratio.
I should mention that while I have driven pickup trucks my entire adult life and have towed stock trailers as well as travel trailers for over 30 years, I am no mechanic nor professional driver and certainly no expert!
But I have come to the conclusion that it simply comes down to how fast one tows/drives. I drive empty at 65-70 mph and I tow around 65-68. If I wanted to zip along at 80 mph and did that often, the 3.42's would really shine! If I towed at 55-60 mph (as we must in CA) then the 4.10's would be ideal....but I do neither! For MY speeds, the 3.73's are a great middle ground...or "compromise" if you must. I don't mind a "compromise" when it is beneficial to me! The more I drive and tow the more I consider the 4.10's...because I don't always feel comfortable towing at 68 and I am in the mountains a lot and I AM getting older! (63 as I sit!) if I were running empty between LA and Phoenix, the 3.42's would be great! But those days are behind me and probably not returning!
I think it is obvious that all three set ups will work...but since we have the chance to drive the perfect tow beast, you might as well tune your ride to your driving habits.
As an aside, the travel blog "Roads Less Traveled" has a great article on the process they took (2 years!) to get their perfect tow beast...and they have a lot of great articles about their 10 years of full time travels.....I've never met the authored and have NO relationship with them....but great reads"
 
Bob Knepper said:
Well, I guess I will throw my two cents in! I bought my 2017 DRW Mega-Cab 4x4 with the Aisin and 3.73's last April. I live in Monument CO which sits between Denver and Colorado Springs at about 7300 feet of elevation. My truck now has a touch over 30,000 miles, probably 75% or better towing our 15,000 39 foot fifth wheel...we are now "full timers". Our travels take us out to CA to Sacremento and Napa Valley, down to Bakersfield and Blythe, over to AZ to Phoenix and Tucson, back up to Monument, over to Tulsa and as I write this, I am sitting in an RV park in Panama City, Florida. I write the above, just to give some background for my following thoughts on what constitutes the "ideal" gear ratio.
I should mention that while I have driven pickup trucks my entire adult life and have towed stock trailers as well as travel trailers for over 30 years, I am no mechanic nor professional driver and certainly no expert!
But I have come to the conclusion that it simply comes down to how fast one tows/drives. I drive empty at 65-70 mph and I tow around 65-68. If I wanted to zip along at 80 mph and did that often, the 3.42's would really shine! If I towed at 55-60 mph (as we must in CA) then the 4.10's would be ideal....but I do neither! For MY speeds, the 3.73's are a great middle ground...or "compromise" if you must. I don't mind a "compromise" when it is beneficial to me! The more I drive and tow the more I consider the 4.10's...because I don't always feel comfortable towing at 68 and I am in the mountains a lot and I AM getting older! (63 as I sit!) if I were running empty between LA and Phoenix, the 3.42's would be great! But those days are behind me and probably not returning!
I think it is obvious that all three set ups will work...but since we have the chance to drive the perfect tow beast, you might as well tune your ride to your driving habits.
As an aside, the travel blog "Roads Less Traveled" has a great article on the process they took (2 years!) to get their perfect tow beast...and they have a lot of great articles about their 10 years of full time travels.....I've never met the authored and have NO relationship with them....but great reads"
Click to expand...

If you want to tow at slower, the 3.42 in 5th work great. We at 60-62 in 5th at 1750RPM +/-, and still have the second OD for freeway cruising empty. With 4.10 and mid weight 5th wheels 1st gear is wasted. I get 15-16 around town and can top 20 on the freeway. SnoKing
 
"With 4.10 and mid weight 5th wheels 1st gear is wasted." I completely agree, if I could lockout 1st gear solo I sure would!

My Son's truck is basically the same as SNOKING's only a LB he also has the 3.42's and AISIN. I have towed his with a 14K dump trailer that was WAYYYYY overloaded so his combined was near 28K. I took off on a fairly steep grade with ZERO effort or shudder even turning at the same time. I was AMAZED. My 11 HO with 3.42's towing a similar load and grade you would have to ease into it.

There is a reason the SAE rating for these AISIN 3.42 trucks is so high because it works.
 
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Subscribe
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Back Issues
Subscription Status
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Buyer's Guides
Ram Diagnostic Trouble Codes
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