Towing with a v6 Pentastar and 3.21 differential

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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:

 

Yardbird

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The V6 OHC engine makes its HP over 3000RPM, as does the 3.5 V6 in my wifes Ford Edge. I had to get used to that, and since I have, it doesn't bother me much. I was used to the 1500 RPM huge torque of my Dodge V10 engine.

I have 3.21 in my 2018 Ram. Get a 3.55, otherwise you will have a 7 speed transmission. With 20" tires, the transmission will not go into 8th until past 70 MPH, and only then when going downhill.

You will need 80 MPH on level ground to try to maintain 8th gear, but at 80, the wind resistance is so great, the transmission will change right back to 7th.

Every time I drive my truck I manually limit the gear according to the speed limit on that road. On interstate I never select 8th, as it's useless. I recently took a trip over 1200 miles, and never used 8th, even at 80 MPH. 24 MPG average.

These engines like RPMs, and will not suffer low fuel mileage from light throttle high RPMs.

The main advantages of 3.55s are better take off with higher weights and being able to use all 8 gears. The disadvantages are the transmission changes 3 gears before you get to 25 MPH, and that's about it.

I will sell you a good set of low mile 3.21s if you want them so I can go 3.55, lol. But really, the 7 speed does all I want on lever ground or steep mountains.

I'll put it this way....7th with 3.21s is basically the same RPM as 8th with 3.55s.
 

redvetram

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I had a 2014 (Gen 4) 1500 with the Pentastar V6 8 speed. Towed my horse trailer with one horse just fine. Probably in the 4000# range. And I live in the mountains in ID. Getting a 2nd horse and a bigger trailer added problems. I was now at 6000# and it was OK but tranny fluid would get over 220 degrees on long climbs. I ended up upgrading to a 2019 Classic with the V8. Loved the V6, though and it got much better MPG than the V8. I wouldn’t hesitate to tow your little trailer with it,
 

Jack F

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For a trailer that size and as often as you'll be towing, the V-6 will be plenty. Just look up the specific tow rating AND payload using the vin of the actual truck your looking at to get the most accurate numbers. Just remember the more options the truck has the more it weighs and the less it tows and hauls. Don't forget to deduct for any aftermarket add ons like a tonneau cover and step bars. That'll come off your payload but with a V-6 your payload will be pretty decent.

Will it be an upgrade?
Absolutely.

Edit: Doc is right, you'll still be high in the RPM range but that's where the V-6 makes its power when it's towing. No way to escape that with a V-6 but it'll still be an upgrade. However I do admit that I never towed with a V-6. I've always had a Hemi or a 360 with my '01 Ram.
I there ,just bought 2022 1500 classic v6 pentastar with 3.55, towed my t trailer for 200 k,no problems at aal
 

farout75

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I have had two RAM 1500 with the 3.6 engine. A 2013 and a 2014. 269 Lbs. of torque just is not adequate in towing up hills. Yes you will make it, but the vehicles behind you will be rater hacked off. I had a 3:55 and a 3;21 gear ration and there is not a dimes worth of difference.
 

Yardbird

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I have had two RAM 1500 with the 3.6 engine. A 2013 and a 2014. 269 Lbs. of torque just is not adequate in towing up hills. Yes you will make it, but the vehicles behind you will be rater hacked off. I had a 3:55 and a 3;21 gear ration and there is not a dimes worth of difference.
The only difference between rear gear ratio is what transmission gear would be used when pulling the hill, not overall performance.

269 ft. lbs. can only do so much.
 

NCRaineman

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269 ft. lbs. can only do so mumuch.
Horsepower sells cars, torque wins races. Pentastar only makes 30lb/ft of torque more than the old 3.8L V6. There's just too much truck for it to pull around. Hemi makes 50% more torque.

Fortunately Pentastar will be going away in a few years. They'll run out production then shift to the turbo four like is being used in the latest Wrangler... which is capable of 295lb/ft at 2250 RPM.
 

ramffml

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The only difference between rear gear ratio is what transmission gear would be used when pulling the hill, not overall performance.

269 ft. lbs. can only do so much.

Exactly! The amount of times I see (towing reviews) complaining about how a higher rear axle ratio would have pulled that hill easier... basic math isn't taught properly anymore. If you can't get something so basic right it makes me question the entire review :banghead:
 

howie12

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Jeez, I wish more people learned and understood physics. HP is what does the work and transmissions and rear end ratios cannot multiply HP. They can multiply torque. The torque at the wheels is what matters an a faster spinning engine can take more gear reductions than a slower spinning engine so the torque can be multiplied more at the same road speed. The real difference is the service duty of the engine. The lighter duty gas engines are not designed to put out maximum, or close hp for its whole life. The Cummins diesel can put out a high % of its rated HP for a longer period of time. A classic example is the old Chrysler 4 cyl 2.2 litre engines inthe K-cars of the mid 1980s were nominally 100-110 hp ratings in vehicles but the same engine sold for industrial use driving a genset or welder was rated about 45-50 hp for continuous use. The point is if you are planning on towing 7000 lbs or more with your 1500 for a high % of its life the PEntastar is not the right answer. If you are making a few trips a year it can safely do the job and reward you with better fuels efficiency over the lifetime of the vehicle. SInce I wrote some of my earlier posts about Pentastar towing I bought some equipment at an auction about 400 miles away and made two round trips with a tri axle trailer withthe total load of about 14,000 lbs split between the bed of the truck and the trailer. The load had some significant wind resistance too. THe truck did fine and the engine did fine. I rolled along the normal freeway fine at 60-65 mph and on secondary roads with steeper grades I did slow some, by choice, down to about 45 mph pulling the grade at about 5000 rpms rather than letting it sit at redline to maintain speed. I do 10,000 mile oil changes and do oil testing for fun with each change. I could see no difference in oil test results for the change with the high towing on it. I had no temp problems with engine oil, engine water temp or transmission temp and in fact they all stayed much lower than lighter towing with my 2014 1500 ecodiesel. All my lubes are synthetic.

Now if I was towing like the above example on a regular basis I would not have the PEntastar. But I don't want to buy a truck that I will keep for five years or more based upon the optimum choice for the maximum I might do with it a few times and pay the penalty for the rest of the time. ANyhow, everyone has a different philosophy on these things and some are willing to but for the maximum and pay thepenalty and others buy for their normal usage as long as they can do the unusual safely with some compromises and everything in between.
 
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