Towing

[18CrewDually]

Only in first gear.

And when we're actually towing for miles on end, the 3.92 will want to sit in 7th (or 8th) whereas the 3.21 will want to sit in 6th (or possibly 7th).

I'd rather tow in direct drive vs over drive.

Also we need to be realistic; there are 0 reports of guys blowing ujoints, transmissions, or rear diffs just because they have the 3.21

Lets not invent problems where there are none, these drive trains can take a beating, as long as they're not intentionally abused they will run forever.

No, all the gears.
I'm not inventing problems. I'm telling you it will add more strain as mentioned. Re-read my post. It's facts.

 

[18CrewDually]

This. The 3.21 does not have the mechanical advantage the 3.92 has, so it's going to require more torque to move the same weight. Maybe from the driver's perspective there's little difference using the analogy that 7th gear in one axle ratio is virtually the same as 8th in the other, but in reality the transmission has to deliver more torque, which means it's harder on the clutches as they engage or disengage while shifting. Also, while the power being delivered by the engine may be the same in either case, the motor mounts have to counteract that additional torque. In short, it's harder on the drivetrain.

You get it. Thanks.

 

[yrraljguthrie]

This. The 3.21 does not have the mechanical advantage the 3.92 has, so it's going to require more torque to move the same weight. Maybe from the driver's perspective there's little difference using the analogy that 7th gear in one axle ratio is virtually the same as 8th in the other, but in reality the transmission has to deliver more torque, which means it's harder on the clutches as they engage or disengage while shifting. Also, while the power being delivered by the engine may be the same in either case, the motor mounts have to counteract that additional torque. In short, it's harder on the drivetrain.

That's gobbly ****. Sorry, but it is.

 

[dsherman26]

That's gobbly ****. Sorry, but it is.

Nope, it's elementary physics. Sorry, but it is.

 

[yrraljguthrie]

Nope

 

[18CrewDually]

 

[ramffml]

No, all the gears.
I'm not inventing problems. I'm telling you it will add more strain as mentioned. Re-read my post. It's facts.

Here are the facts; the 1500 with either rear end can't pull a TT much more than 8000 pounds, it's limited by payload.

So at this point we're talking about theoretically damaging a drive train that is rated to tow 8000 pounds, up the davis dam and doing it within a certain amount of time. This 0 to 30 test is the only difference between the trucks, that's what j2807 is testing that makes the 3.21 3000 pounds less than the 3.92.

And getting back to "more strain", what do you think is worse, towing in 7th/overdrive (3.92) or towing in 6th/direct drive (3.21)?

Again, don't invent issues. There are theoretical truths and there are actual realities, and I haven't yet read one report where a drivetrain has been damaged (other than by guys running their trucks on the track every weekend which doesn't count). It's simply a non issue, our drivetrains are strong and durable.

 

[18CrewDually]

My posts went over your head. I'm not going any deeper since you cannot grasp the concept. There's a reason why the engineers have identical trucks, (minus the 2 axle ratios), advertised more than 2,000 pounds (1 ton) difference in towing capacities. If you can't see that in my explanations then I can't help you.

 

[ramffml]

My posts went over your head. I'm not going any deeper since you cannot grasp the concept. There's a reason why the engineers have identical trucks, (minus the 2 axle ratios), advertised more than 2,000 pounds (1 ton) difference in towing capacities. If you can't see that in my explanations then I can't help you.
View attachment 524589

I assure you it's you that's missing the point.

The only reason the 3.92 has the 3000 pound increase in tow rating is due to the 0 to 30 type acceleration tests which are part of j2807. It's not because the 3.21 is less durable or causes more drivetrain stress and will explode if towing 11,000 pounds, its due to 0 to 30 acceleration tests in the j2807.

There are 0 reports of the 3.21 eating itself under load while towing.

 

[crash68]

It's not because the 3.21 is less durable or causes more drivetrain stress and will explode if towing 11,000 pounds,

This might be true if the transmission never has to shift gears.
It goes in both directions, the power going to the rear end maybe the same but the resistance coming back is not. This has to be taken in account for any clutch or viscous coupling type in a drivetrain.

 

[turkeybird56]

If you would check the rating charts that were posted, you will not find any 1500 with the Towing weight you suggested in your original post. I had an old 2006 F250 Diesel, and it was rated for only 12,500. My 2019 RAM 2500 6.4 gasser is rated for over 14,000 lbs. The tech has improved, but on many of the 1500, if not all, the brakes, wheels, axels, suspension, and frames are still smaller and lighter. You will be able to tow any weight you like, until something gives up. It's a matter of time and what goes first. Pay little attention to me, I'm just an old guy with a smart phone. The salesmen know way more than me.

Yahoo, the ever important multi talented, all know many faceted salesman. YUP, they got it down, (tongue in cheek, sic).

 

[turkeybird56]

Just my opinion and a thought, skeery.

IF I had a need to pull anything over 8,000 lbs a lot of the time, I would be in a HD, 2500, but that is just me. I only tow a lil, and that would be with a Stock Trailer (2,150) lbs loaded with 40-44 bales of hay, so I am well within the limits. That would be 3000-4000 lbs of hay. Truck pull it all day long, the hard part is loading it and unloading it, it being a stock trailer. Well within the 6,600 lb rating of my stock trailer, of total GVW.

Love the banter back and forth. Makes me do a lil research and learn also.

 

[tron67j]

Yep, all been discussed repeatedly. Just focusing on the original posting, errors abound in it. Starts off saying max towing capacity. Towing capacity and max trailer capacity are 2 different things. Towing us based on payload capacity, trailering is just how much can be dragged behind ignoring all other factors. Second, no date given for vehicle so who knows really what we are talking about. Third, using the word "any" to talk about the max weight then qualifies with engine type. Then further qualifies by differentiating if straight or 5th wheel towing.

So many variables, this conversation can lead to do many tangents that in the end there is possibly no way to disconnect good advice from bad.

Discussions like these, in order to be helpful especially months or years later, need a specific focus to be of real value: either person wants to tow X and needs to know what to buy, or person has Y truck and wants to understand towing and trailering capabilities.

Gears are but one factor, can't assume all vehicles with same gear can do exact same thing.

 

[Riccochet]

You run out of payload long before you run out of towing capacity. Most of the time, anyways. There are a few truck configs that get you a lot of payload, like a RCLB.

Also worth mentioning that max tow comes with increased oil and trans cooling capacity.

Realistically, if you're towing over 8000 lbs, depending on what you are towing, a 1/2 ton truck is nearing it's limits.

 

[yrraljguthrie]

Those people saying shifting down a gear will increase strain on the transmission are making up stuff and calling their ideas "physics".

 

[yrraljguthrie]

Also worth mentioning that max tow comes with increased oil and trans cooling capacity.


Max Tow Package that includes 18-by-8-inch wheels, a 3.92:1 axle ratio, a full-size spare tire, LT275/65R18 tires and the Trailer-Tow Group. The Trailer-Tow Group includes a Class IV receiver hitch, trailer tow mirrors and trailer brake controller. Nothing said about changes in oil and transmission cooling. That would require a change in transmission...which doesn't happen. Same part number same transmission.

 

[ramffml]

This might be true if the transmission never has to shift gears.
It goes in both directions, the power going to the rear end maybe the same but the resistance coming back is not. This has to be taken in account for any clutch or viscous coupling type in a drivetrain.

So you do have reports of the 3.21 exploding the drive train?

The j2807 tests 0 to 30. That's why the 3.21 has a 3000 pound lower tow rating, due to it having less initial tug off the line.

There is no engineering documentation, stress tests, or reports showing that the 3.21 can't actually tow 11,000 pounds without grenading itself. There is just a very specific acceleration test in the j2807 that says it can't launch from a dead stop up a hill towing X pounds within Y seconds.

For all we know the 3.21 drivetrain can pull 15,000 pounds every day for 200,000 miles and never have any issues other than reduced speed starting from a stop.

 

[yrraljguthrie]

Ramffml, finally some truth. Good post.

 

[crash68]

So you do have reports of the 3.21 exploding the drive train?

The j2807 tests 0 to 30. That's why the 3.21 has a 3000 pound lower tow rating, due to it having less initial tug off the line.

Your the only one talking about exploding drivetrains.
If you take two identical trucks and trailers with the only difference being rear axle gear ratio on a 30 roll guess who will be looking at taillights.

Something else to keep in mind that transmissions nowadays shift in part by torque demand, not at any on given/set rpm. Clutch engagement and torque converter lock up are all controlled based on how much torque is being demanded.

 

[ramffml]

Your the only one talking about exploding drivetrains.

No actually the poster above you was talking about drive train stresses. I think you're getting lost here.

If you take two identical trucks and trailers with the only difference being rear axle gear ratio on a 30 roll guess who will be looking at taillights.

We've been through this ad nauseum when it comes to acceleration. The only difference is from a dead stop. If both trucks are already rolling or on an onramp or passing a semi - there is no difference.

Something else to keep in mind that transmissions nowadays shift in part by torque demand, not at any on given/set rpm. Clutch engagement and torque converter lock up are all controlled based on how much torque is being demanded.

That has no bearing on this discussion as that effects both drivetrains equally once both are in the same final gear ratios.