2023 5.7L V8 HEMI MDS VVT eTorque Engine 3.21 Rear Axle Ratio

[AndoTX]

Hey ya'll this is my first post and super happy to have found the community. Bought a 2023 RAM (engine specs in title) and towed my new 2022 Grand Design MK200 travel trailer from TX to GA about ~1,000 miles. I've read some of the posts here and I've found what you guys have said to be extremely accurate, specifically the part about with a 3.21 rear axle ratio in the 1500 how it is most efficient at towing speeds 48-57 MPH. I set my cruise control at 57 MPH on all flat dry roads, could hit 60 MPH on a downhill, and had to back it down to either 54 MPH, 52 MPH, or 50 MPH on all hill climbs depending on steepness of the grade. As others have said here I'm just a little uncomfortable with 57 MPH being my top highway speed pulling this 6,500 lb trailer. Lots of highways with 70 MPH limits and I'm in the far right lane (or sometimes one lane with a line of unhappy people behind me) going 50 crawling up the moderately gentle hills coming into GA. I feel I'd never have a chance at ever taking the trailer to Colorado, Oregon, or even North Carolina where the hills will only get more aggressive. I mean, what would i do crawl up more agressive hills at 35/40 MPH in 70 MPH speed limits? Just feels like I need a bit more power here.

Basically reading that the 3.92 rear axle ratio is more efficient at 58-70 MPH which sounds awesome to be able to maintain 65 MPH and have the truck feeling happy to do so and maintain it. So thinking about just swapping trucks to get the 3.92 rear axle ratio in hopes of maintaining 65 MPH highway speeds. Also read I will lose a little mpg but that's ok. Only other option I'm considering is going for the diesel, but I see most have tow capacity of around 9,600 lbs in the 3.92 rear axle ratio. That's not much more tow capacity than I have right now at 8,200 lbs. If I stick to regular gas and go for the 3.92 I get 11,200 tow capacity.

I'm pretty close to just going out and swapping for my exact same Ram truck (2023 5.7L V8 HEMI MDS VVT eTorque Engine) but just doing a 3.92 rear axle instead of the current 3.21. Anything I'm missing here or fairly spot on? ** FYI I know I could push my current 3.21 past 57 MPH it just felt like 57 MPH was it's happy zone to maintain on flat roads. Anytime I pushed past that, it did it, it just felt like I was asking a bit too much from the vehicle. Any thoughts appreciated and thanks form a first time Ram owner!

 

[crash68]

I know I could push my current 3.21 past 57 MPH it just felt like 57 MPH was it's happy zone to maintain on flat roads. Anytime I pushed past that, it did it, it just felt like I was asking a bit too much from the vehicle.

Is it temperatures that are making you think your asking too much? If so what are the temps your seeing?

If it's the engine rpms that are making you think your asking too much, your worrying for nothing. The torque band for the 5.7 Hemi is up around 4K rpms. If you want a ballpark of where the engine will spinning with the 3.92 gearing, use the ERS to lower the gear one. Contrary to popular belief, it's torque that tows a trailer not horsepower. Seen it many times people expecting to see 2K rpms while towing with a Hemi, to that I reply you should have bought a diesel. For comparison the Hemi torque peak is 410 ft.lbs @ 4K rpms, the EcoDiesel is 480 ft/lbs @ 1600 rpms.

 

[CanRebel]

If your not comfortable with it. Why not look at 2500?

I've towed very close to limits with my 1500 Rebel. It does have 3.92 but that shouldn't matter all that much once you up to speed. mostly at stop/go.

What is your issue going faster? RPM ? sway?

Gas engine will have higher RPM. Diesel will not.

 

[GRKN]

Just regear your truck if you really want 3.92. Pretty simple

 

[ramffml]

There will be no difference towing at 58 to 70 mph with the 3.92 vs the 3.21. You'll just use a different transmission gear, but the power output (or lack thereof in your case) and RPMS will be 100% the same.

Where you'll notice the difference is when both trucks are in first and then pulling out from a dead stop. But at those speeds you mentioned, literally 0 difference.

Couple questions:
What truck did you have before this?
What makes you think your truck can't pull that load at 60 mph, just the RPMS?

 

[ramffml]

For reference, here is why you won't notice a difference between 3.21 and 3.92. This chart has the RPMs both trucks will be at, at 65 mph.

If your truck (3.21) was in 6th gear holding steady at 65, then with the 3.92 it will be in 7th instead (the blue cells); but note the RPMS, 2191 vs 2194. No difference.

If your truck was in 5th instead @ 2870, then the 3.92 will be in 6th (green cells) at 2675. A LOSS of 195 RPMS (less power), or, it might be in 5th as well at 3505 RPMs.

 

[Daw14]

Let it break-in , then see how it feels.

 

[turkeybird56]

The difference between the 3:21 and 3:92 just negatable in the end. U are not maxed out, but are getting there, and I bet your trailer is more than 6500 lbs dry weight. Also, did you use a WDH setup? Sounds like instead of a re-gear, time for you to go up to the 2500 with 6.4 gasser. Just IMHO. If you tow that weight all the time, Diesel 2500. If just infrequent towing, the 6.4 be good for your needs.

 

[Tulecreeper]

The difference between the 3:21 and 3:92 just negatable in the end. U are not maxed out, but are getting there, and I bet your trailer is more than 6500 lbs dry weight. Also, did you use a WDH setup? Sounds like instead of a re-gear, time for you to go up to the 2500 with 6.4 gasser. Just IMHO. If you tow that weight all the time, Diesel 2500. If just infrequent towing, the 6.4 be good for your needs.

That trailer lists as 4,915# UVW, with 2080# of cargo capacity for a GVWR of 6995#. If the OP's actual towing capacity is 8200#, and even assuming he has the trailer maxed out at the 6995# GVWR - which is highly unlikely as 2000# of cargo is a lot of cargo - he still has a relatively comfortable 15% safety margin which is the minimum I try to maintain when I'm towing. Assuming he hasn't maxed out or gone over his rear GAWR, a WDH only distributes the hitch weight further forward toward the front axle so you have better steering control. I would like to know how much actual hitch weight he is dealing with, however. Travel trailers are more often than not notoriously much heavier in the front than they advertise. I've seen many that are as much as 25% - 30% heavier than they state in the specs. If it is well over his max it's squashing his suspension and that could be part of the issue.

 

[turkeybird56]

That trailer lists as 4,915# UVW, with 2080# of cargo capacity for a GVWR of 6995#. If the OP's actual towing capacity is 8200#, and even assuming he has the trailer maxed out at the 6995# GVWR - which is highly unlikely as 2000# of cargo is a lot of cargo - he still has a relatively comfortable 15% safety margin which is the minimum I try to maintain when I'm towing. Assuming he hasn't maxed out or gone over his rear GAWR, a WDH only distributes the hitch weight further forward toward the front axle so you have better steering control. I would like to know how much actual hitch weight he is dealing with, however. Travel trailers are more often than not notoriously much heavier in the front than they advertise. I've seen many that are as much as 25% - 30% heavier than they state in the specs. If it is well over his max it's squashing his suspension and that could be part of the issue.

Yeah, just hard to say. PPL forget about propane weight, and grey water weight, and water weight, and and. I pull 6-7K locally some times a year, as in trailer and hay, but since local, not concerned. If I was traveling pulling a big RV and family and stuff, I would be REAL tuned into what was happening and weights. Really depends what OP is trying to do, and where he is pulling, etc.

 

[AndoTX]

Is it temperatures that are making you think your asking too much? If so what are the temps your seeing?

If it's the engine rpms that are making you think your asking too much, your worrying for nothing. The torque band for the 5.7 Hemi is up around 4K rpms. If you want a ballpark of where the engine will spinning with the 3.92 gearing, use the ERS to lower the gear one. Contrary to popular belief, it's torque that tows a trailer not horsepower. Seen it many times people expecting to see 2K rpms while towing with a Hemi, to that I reply you should have bought a diesel. For comparison the Hemi torque peak is 410 ft.lbs @ 4K rpms, the EcoDiesel is 480 ft/lbs @ 1600 rpms.

Thanks for the reply! Yeah first time tower with 6,500 lbs behind me. Lol I never even paid attn to the temperature (noted) Yeah it's the engine rpm's making me think I'm asking too much. Torque tows a trailer (noted) Yes was trying to keep it 2k rpm's towing with the Hemi V8 etorque. Ok so if it pops up to 4k rpm's not a big deal and nothing to worry about it seems. Again first time tower with 6,500 lbs. Yeah sounds like the EcoDiesel may have been a better choice for me. But I'l hang onto this truck for a while since I just bought it lol prefer not to lose $10k immediately on trade in.

How long can I be between 3k and 4k rpms running with this engine and everything still totally fine? Also would you reccomend I leave tow mode on the entire time? Any reason to take it out of tow mode occasionally or just on 100% of the time? Thanks in advance for the thoughts!

 

[AndoTX]

If your not comfortable with it. Why not look at 2500?

I've towed very close to limits with my 1500 Rebel. It does have 3.92 but that shouldn't matter all that much once you up to speed. mostly at stop/go.

What is your issue going faster? RPM ? sway?

Gas engine will have higher RPM. Diesel will not.

Just replied to @crash68 explaining the whole sitch. It is basically the rpm's heading up toward 3500-4000 that made me think this.

 

[AndoTX]

There will be no difference towing at 58 to 70 mph with the 3.92 vs the 3.21. You'll just use a different transmission gear, but the power output (or lack thereof in your case) and RPMS will be 100% the same.

Where you'll notice the difference is when both trucks are in first and then pulling out from a dead stop. But at those speeds you mentioned, literally 0 difference.

Couple questions:
What truck did you have before this?
What makes you think your truck can't pull that load at 60 mph, just the RPMS?

Just replied to @crash68 explaining the whole situation. This is my first truck! Yeah just the RPM's getting in the 3500/ 4000 zone but after reading some of these replies seems totally normal. I towed a jet ski and a 3500lb camper before this with a 2018 Jeep Grand Cherokee V6 with 6200 tow capacity. Now I got the 2023 Ram Hemi V8 etorque pulling a 6,500 travel trailer. So sounds like this is just my first time pulling this much weight behind me and hearing it get up toward 4000 rpm's is new to me. Seems like being in that for too long would just tank your towing mpg's.

 

[AndoTX]

For reference, here is why you won't notice a difference between 3.21 and 3.92. This chart has the RPMs both trucks will be at, at 65 mph.

If your truck (3.21) was in 6th gear holding steady at 65, then with the 3.92 it will be in 7th instead (the blue cells); but note the RPMS, 2191 vs 2194. No difference.

If your truck was in 5th instead @ 2870, then the 3.92 will be in 6th (green cells) at 2675. A LOSS of 195 RPMS (less power), or, it might be in 5th as well at 3505 RPMs.

View attachment 523009

Thanks for this! Yeah concern in going over 57mph is/was definitely rpm's. So sounds like EcoDiesel may have been the way for me to go. Question then why do people go for the 3.92 rear axle ratio?

 

[AndoTX]

The difference between the 3:21 and 3:92 just negatable in the end. U are not maxed out, but are getting there, and I bet your trailer is more than 6500 lbs dry weight. Also, did you use a WDH setup? Sounds like instead of a re-gear, time for you to go up to the 2500 with 6.4 gasser. Just IMHO. If you tow that weight all the time, Diesel 2500. If just infrequent towing, the 6.4 be good for your needs.

Trailer is 5,400 lb dry weight and I prob got 1,000 worth of stuff in there. GVWR on the trailer is 6,995 lb. I estimate I'm pulling 6500lb with my stuff in there right now.

 

[Tulecreeper]

Just replied to @crash68 explaining the whole situation. This is my first truck! Yeah just the RPM's getting in the 3500/ 4000 zone but after reading some of these replies seems totally normal. I towed a jet ski and a 3500lb camper before this with a 2018 Jeep Grand Cherokee V6 with 6200 tow capacity. Now I got the 2023 Ram Hemi V8 etorque pulling a 6,500 travel trailer. So sounds like this is just my first time pulling this much weight behind me and hearing it get up toward 4000 rpm's is new to me. Seems like being in that for too long would just tank your towing mpg's.

No one who buys a truck for towing gives even the slightest thought to MPG.

 

[AndoTX]

That trailer lists as 4,915# UVW, with 2080# of cargo capacity for a GVWR of 6995#. If the OP's actual towing capacity is 8200#, and even assuming he has the trailer maxed out at the 6995# GVWR - which is highly unlikely as 2000# of cargo is a lot of cargo - he still has a relatively comfortable 15% safety margin which is the minimum I try to maintain when I'm towing. Assuming he hasn't maxed out or gone over his rear GAWR, a WDH only distributes the hitch weight further forward toward the front axle so you have better steering control. I would like to know how much actual hitch weight he is dealing with, however. Travel trailers are more often than not notoriously much heavier in the front than they advertise. I've seen many that are as much as 25% - 30% heavier than they state in the specs. If it is well over his max it's squashing his suspension and that could be part of the issue.

the trailer is exactly 5,368 UVW, I think I have ~1000 lb worth of stuff in the trailer, and yeah max GVWR is 6995. I am usuing a Blue Ox WDH rated for 800-1000 lb toungue weight. I estimate my tongue weight is ~900 lb but I just bought a etrailer tongue weight scale I'm going to find out for sure.

 

[AndoTX]

Yeah, just hard to say. PPL forget about propane weight, and grey water weight, and water weight, and and. I pull 6-7K locally some times a year, as in trailer and hay, but since local, not concerned. If I was traveling pulling a big RV and family and stuff, I would be REAL tuned into what was happening and weights. Really depends what OP is trying to do, and where he is pulling, etc.

No water weight whatsoever I empty all tanks before I pull. I've only pulled from TX to GA so far and planning/ hoping to head to NC, CO, and OR. I do leave the propane tanks on the trailer when I pull, should I take those off the trailer and put in truck bed? As long as I have Payload available for that?

 

[AndoTX]

No one who buys a truck for towing gives even the slightest thought to MPG.

Haha that's funny. Noted.

 

[ramffml]

You should be able to maintain 63 mph at about 2300 RPMs on straight roads with little to moderate headwind - all with 0 issues. Then if you need to pass or go up a slope/hill, it will downshift and scoot up to 2800/3500/4000 etc.

That's normal. Nothing wrong with your truck, that's how all gassers tow.