Towing with a v6 Pentastar and 3.21 differential

farout75

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Hi,

I've been doing a lot of research on the 2019 or newer Ram 1500 Big Horn. I took a 2019 with a v6 Pentastar / 3.21 differential for a test drive and really liked it. The problem I have is a lot of discussion about the v6 includes opinions from people who have had the v6 in trucks from 20 years ago. The new v6 seems to put out more HP than a lot of v8's from 20 years ago.

Here's my current situation: I currently drive a 2008 Honda Ridgeline (5,000 lb towing capacity) (I know...not a real truck, but it's been an outstanding vehicle). I commute round trip to work about 40 miles a day. This is the primary use of my vehicle. However, I also have a small travel trailer (17' R-Pod, about 3,000 lbs). Once a year, we pull the travel trailer from WI and go somewhere in the mountains out west (Montana, Wyoming, Colorado, etc.). I've pulled this trailer thousands of miles with my Ridgeline (including through the mountains. The Ridgeline handled it well, although there were a lot of 4,000 RPM slow climbs. The vast majority of the time, my vehicle is used on the highway as a commuter vehicle.

I need to replace my Ridgeline. I always said that I'd like my next truck to have a bit more towing capability than my Ridgeline. We have no intention of ever pulling a big camper. However, we may get something slightly larger than our R-Pod. Maybe something like 500 lbs. heavier.

Everybody says "buy the v8". I'm just trying to figure out if it's truly necessary in my situation? Yeah, the power is fun, but I'm kind of past needing to drive a rocket. Is it worth a higher purchase price / lower fuel economy for the 1 trip each year that we take? Would the v6 with the 3.21 be an upgrade over pulling with my Honda Ridgeline?
Having owned two RAM 1500 with the 3.6 I feel I am a good person to give you my opinion. The 3.6 should do fine. The 269 lbs of torque is light but can do what you want. I encourage you to get the Mopar 84 month unlimited mileage warranty. The 3.6 is not without its issues just like the 5.7. Take a radiator is close to $1400 if something happens. So go for it!
 

farout75

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What about the 3.55 differential? Would I have less 4,000 RPM climbs than the 3.21?
There is very little noticeable difference between the 3:55 and the 3:21. Only about a extra thousand pounds of towing. MPG is somewhat noticeable over the 3:55 by about 2 mpg.
 

olscout

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I have a 2016 Ram with the same set up. I bought it expecting to use my " beater" truck to tow. Last year, I was stuck and had to use the Ram to tow a 20' steel car trailer from Northern Indiana to South Carolina empty, and back again loaded with a 73 International 1210 Camper Special (heavy!). It did work on hills for sure, but I had deleted all but the top and bottom grille shutters, and the transmission cooler thermostat. Even pulling hard, temps never got over 215 on the biggest hill, 185 on transmission. This summer I pulled my Scout II down to Tennessee, hills were a lot shorter and I was pulling a Featherlight aluminum trailer. No issues, and on both trips I averaged 13-14 mpg. For what you're towing, it shouldn't be much of a problem, just be prepared for some higher rpms at times.
 

Willie Mosher

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Okay look like the v6 I have one in 2 door jeep.
As pull trailer In Co&Wy your going need look 3.55 or 3.92,

I had 3.21 in my jeep ( same v6)
I had to rehear it before 6000 miles on it. This was costly mistake,

I’ll lost maybe 1.5 mpg in man 6sp
3.21 to 4.11 is big difference but w
8sp automatic 3.21 to 3.55

More like cost less then 10 gallons a year.
 

gfh77665

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Lots of great information here, but its on the verge of overthinking.

You stated its a small TT (3000 lb) and you pull it ONCE a year, with no intention to buy a heavy one.

Easy conclusion, buy Pentastar with 3.55 gearing. Its a great combo / choice that will provide you excellent fuel economy 99.9% of the time and still be able to accommodate towing very well during your annual trip.
 

howie12

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AS an owner of a 2020 Longhorn crew cab, Ram box 4x4 truck with the V-6 Pentastar and the 3.55 rear end ration and having towed ~7000 lbs gross on a tandem axle flatbed with low wind resistance with it from Eau Claire to Iron RIver and also having towed a single axle, V-nose 7'high by 12' long snowmobile trailer with an estimated gross load of 2500 lbs it tows both well and yes it does rev up a bit but seldom over 3500 in my experience. I think either rear end ratio will pull your trailer fine. Given that it is a once a year trip I would make my choice based upon the rest of your driving. If your commuting is longer distances and at high speed (65 and higher) I think the 3.21 would be the right choice. If your commute is more in the 50-55 mph range I think the 3.55 would be better for you. While my truck will get into 8th gear at 45 mph or so with no headwinds and no uphill grade any bit of grade causes it to downshift. Up at 55-60 the engine is spinning fast enough but still slow that it pulls a bit of headwind, or acceleration or uphill with much less shifting.

FOr myself I don't mind the shifting and the higher rpms. The transmission shifts so nicely and the engine is quiet with no intake roar or exhaust roar that the up and down shifting in gears 6-8, which are relatively close together, is nearly unnoticeable, a downshift to 5th is noticeable but on objectionable to me and one to 4 th is more noticeable.

300hp is plenty of power to do what you want and contrary to what some say it is hp that does the work of pulling and the transmission, rear end and torque converter that multiply the torque to get you what you need to pull what you are pulling.
 

howie12

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I also should have added that when I ordered my truck the 3.55 choice gave a rated towing capacity of about 7000 lbs and the 3.21 was a 2 or 3 thousand pounds less. The 3.92 was available then with the V-6 too and it did not change the tow rating at that time.
 

ramffml

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AS an owner of a 2020 Longhorn crew cab, Ram box 4x4 truck with the V-6 Pentastar and the 3.55 rear end ration and having towed ~7000 lbs gross on a tandem axle flatbed with low wind resistance with it from Eau Claire to Iron RIver and also having towed a single axle, V-nose 7'high by 12' long snowmobile trailer with an estimated gross load of 2500 lbs it tows both well and yes it does rev up a bit but seldom over 3500 in my experience. I think either rear end ratio will pull your trailer fine. Given that it is a once a year trip I would make my choice based upon the rest of your driving. If your commuting is longer distances and at high speed (65 and higher) I think the 3.21 would be the right choice. If your commute is more in the 50-55 mph range I think the 3.55 would be better for you. While my truck will get into 8th gear at 45 mph or so with no headwinds and no uphill grade any bit of grade causes it to downshift. Up at 55-60 the engine is spinning fast enough but still slow that it pulls a bit of headwind, or acceleration or uphill with much less shifting.

FOr myself I don't mind the shifting and the higher rpms. The transmission shifts so nicely and the engine is quiet with no intake roar or exhaust roar that the up and down shifting in gears 6-8, which are relatively close together, is nearly unnoticeable, a downshift to 5th is noticeable but on objectionable to me and one to 4 th is more noticeable.

300hp is plenty of power to do what you want and contrary to what some say it is hp that does the work of pulling and the transmission, rear end and torque converter that multiply the torque to get you what you need to pull what you are pulling.

Torque is what matters. That's why a cummins diesel with "only" 420 hp (but 1,075 lb/ft of torque) can tow 35,000 pounds but the 6.4 hemi with 10 less hp and two more gears can tow only half of that.
 

BuschLatte420

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The 3.6L has better horsepower and torque specs than the Ridgeline, also the ZF 8SP transmission has a lot better gear stager. It should tow your trailer nicely.

As for the rpm issue, torque is what pulls a load. A gasser engine needs to rev to get where the torque band/peak is which is usually in the 4K rpm range. If you want to tow a trailer at 2K rpms buy a diesel, theyre torque band is around 2K.
3.6 does not have a ZF tranny does it? I thought that was a hemi thing and the v6 had the regular Chrysler 8 speed?
 
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ramffml

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3.6 does not have a ZF tranny does it? I thought that was a hemi thing and the v6 had the regular Chrysler 8 speed?

It's a ZF 8 speed, though not the exact same one as the one in hemi. There is some variations there, some ZF's are built by chrylser in their own factory, others are pure ZF. I believe the 3.6 is chrylser built, but still very solid.

Completely different than the 6 speed FCA transmissions which are pure FCA.

Edit: found this link which has a great summary:

 
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