I pull a fairly heavy fifth wheel RV at around 21,000 pounds. Looking at ordering a 2021 3500 Club Cab dually with the HO and Aisin. This comes standard in 3.73 rear axle. A friend is recommending a 4.10 axle as he is concerned that the Aisin trans might hunt a lot with that weight. My fifth wheel is well within the towing capacity of either ratio of anywhere from 33K to 35K. Would like to hear from owners of similar 2019 or 2020 3500 trucks that pull trailers in the low 20K as to how their transmissions perform. I currently am pulling with a 2003 HO Cummins with a 6 speed manual trans and 4.10 axle but I am exceeding the rated towing capacity of the truck so it is time for a new one. C
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Rear axle ratio recommendation
- Thread starter CdnHO
- Start date
The Aisin is what you want, never had it hunt gears and have never heard that complaint from anyone. I also recommend the 4:10, I only pulled about 18000 with mine and loved it. I previously had a 68RFE and it was no comparison to the Aisin, never could get a jerk at low gears out of it.
I would go 4.10 on the dually.
You'll sacrifice some mileage running empty, but the max tow capability is worth it.
My 3.73 geared SRW HO pulls my 16K effortlessly with almost no hunting 99% of the time, but I typically lock out 6th if I'm pulling a big hill and feel it's upshifting too soon to maintain speed.
You'll sacrifice some mileage running empty, but the max tow capability is worth it.
My 3.73 geared SRW HO pulls my 16K effortlessly with almost no hunting 99% of the time, but I typically lock out 6th if I'm pulling a big hill and feel it's upshifting too soon to maintain speed.
carlrx7
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What's your preferred speed to tow; 5 above or 5 below? What RPM range do you like to be at? Each gear ratio will have it's own "weak" area, where RPMs are kinda high or kinda low.
3.73's @ 60 = 1810 rpm in 5th...1500 in 6th
4.10's @ 60 = 2000 rpm in 5th...1630 in 6th
3.73's @ 65 = 1960 rpm in 5th...1620in 6th
4.10's @ 65 = 2170 rpm in 5th...1780in 6th
3.73's @ 70 = 2110 rpm in 5th...1750 in 6th
4.10's @ 70 = 2320 rpm in 5th...1900 in 6th
Overall, 3.73's will give you either 5mph more @ same RPM or 200 rpm less vs the 4.10.
If I was towing 21,000 lbs, i'd just go with the 4.10's and forget about it.
3.73's @ 60 = 1810 rpm in 5th...1500 in 6th
4.10's @ 60 = 2000 rpm in 5th...1630 in 6th
3.73's @ 65 = 1960 rpm in 5th...1620in 6th
4.10's @ 65 = 2170 rpm in 5th...1780in 6th
3.73's @ 70 = 2110 rpm in 5th...1750 in 6th
4.10's @ 70 = 2320 rpm in 5th...1900 in 6th
Overall, 3.73's will give you either 5mph more @ same RPM or 200 rpm less vs the 4.10.
If I was towing 21,000 lbs, i'd just go with the 4.10's and forget about it.
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Thanks. It appears that all are pointing to 4.10 ratio. Max Tow Package: ✅
Big Booty Judy
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My trailer is also 21k and I too just ordered my 3500 drw with 3.73. With a 1075 little torques under there and a towing capacity of 33k that is far more that enough. Why is it so worth it to have max tow capacity if you will never ever use it?
Nick
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It is getting the trailer moving . I have 373 with a 14000 k 5th wheel works great. Personally I would go with 410 with a 21 k trailer that 75 lbs of torque is really not that much . Just my opinion . Thats plot of weight to get rolling from a stop in the middle of a hill .
H3LZSN1P3R
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I know you already ordered the truck OP but still For me the question really is how much are you going to be towing that 21k vs driving empty/ less than 10k in tow... if the majority of the kms is unloaded or less than 10k weight then 3.73 and you will have better millage and when you tow the camper you wont struggle but it wont pull as good as 4.10s..... i have towed with lots of gear ratios from 3.21 to 4.56 the difference you will expeirence between 3.73 and 4.10 loaded is very minimal but the unloaded driving you will appreciate 3.73 much more
davis2
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I bought a used truck with a 3.42. My TT is only 900lb max, so I'm ok.
NDanecker
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I had a 13 DRW 68rfe with 3.42 and quickly ordered a 14 DRW AISIN with 4.10 because I didn't like how it hunted for gears on the highway. Getting started from a stop also felt like a struggle. I had a GN dump that I towed with both vehicles where I was maxed out getting gravel (truck and trailer was ~32k local roads). I had the 14 truck until 19 when I went to a 1500 after selling the GN dump and not needed to tow but yesterday ordered a 21 DRW AISIN with 3.73. We are in the market for an RV to take harleys for trips out west and I just couldn't find the right RV within the capacity envelope of the 1500 (whole other topic). Anyways, I feel the lower first gear in the AISIN will give me the initial pulling grunt to get moving with AISINs lower first gear ratio and the 3.73's will help lower the RPMs on the highway even when towing. I agree with others the 4.10 setup is a beast for towing, but I couldn't really run 80 on the highway empty. Truck did it but didn't seem to like it. 65 or so was its happy place idling along getting best mileage. I'm hoping the 3.73 will help when not towing as I like to drive a little faster when empty then grandma in the right lane. LOL.
My thoughts on it.
My thoughts on it.
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davis2
Active Member
When spring hits, I'm going to weigh the truck and trailer and report back. My truck didn't struggle at all with my combo, but haven't been on the interstate while towing. I'm thinking the 3.42's will shine there!
davis2
Active Member
Wonder why it did that? I really don't have many miles of towing with mine, Covid slowed our travel way down. I do get about 20 mpg highway unloaded at 75 mph
my personal experience is I am towing approximately 40-45% of the miles. My last vehicle in a year I had 45000 miles, and approximately 19000 miles towing 18-20000#. the majority of my driving was empty in which I appreciate the 3.73 gear ratio versus the 4.10’s. Many times I would travel with a coworker, he had the 4.10’s. We were following each other, at slower speeds 65ish, he did better, at 70-75MPH states I did better on the mileage. We weighed within 400# of each other gross weights. So I would believe that would be a pretty good comparison. But that is just my personal preference, and opinion
I am retired and put on about 10 thousand a year. However I tow about 70 to 80 % of those miles becasuse of long trips. The rest of the time she is my main transportation for groceries, etc. So towing is my main use miles wise.
Wish I was retired, i tow coast to coast quite a bit, int the last few Years I have needed the tow capacity, but it is also my daily driver, in which my round trip is close to 60 miles per day. I doubt I am saving much fuel with the 373’s but every bit helps, and I haven’t had issues pulling the grades in the north and west. They are both great rigs. I’m really enjoying my 3500. Hope you do as well.