Camper towing report after 3200 miles

[UWSkier]

We're about 3200 miles into a 4000 mile round trip from Arizona to WI and back via Colorado.  I did this trip last year in my 2016 Denali half ton with the 5.3L and 8 speed for comparison.

 

I'd say the Allison and 6.6 gas combo is "just OK."  It REALLY loves to drop down into 6th gear and rev to about 3250-3500 RPM on almost any hill, and it struggles to stay in 8th gear on the flats if the headwinds are over 7 MPH.  Granted, I tow pretty fast around 70-72 MPH.  But I expected more out of the big gasser.  I know it's not a diesel, but I figured it'd race up the grades my old 5.3L did at 4500 RPM down around 3000 RPM or so.  Climbing the Mogollon Rim in AZ, this was not the case.  Maybe closer to 4500 RPM vs 4000 RPM.  Maybe I just had a really strong 5.3!

 

The chassis is great, and so is the tech.  The truck is certainly more composed than the half ton was handling-wise, and I barely run any weight distribution at all, which improves the ride.  It gets about 1 MPG better than the Denali did towing, but it's an absolute thirsty pig not towing.

 

I'm still happy with the decision.  I don't mind the sound of a V8 doing work, and the transmission stays cool even in AZ.  Just expected a bit more jam.  Feels like GM left a ton on the table with this engine.

Edited August 9, 2023 by UWSkier

[Pryme]

13 hours ago, UWSkier said:

We're about 3200 miles into a 4000 mile round trip from Arizona to WI and back via Colorado.  I did this trip last year in my 2016 Denali half ton with the 5.3L and 8 speed for comparison.

 

I'd say the Allison and 6.6 gas combo is "just OK."  It REALLY loves to drop down into 6th gear and rev to about 3250-3500 RPM on almost any hill, and it struggles to stay in 8th gear on the flats if the headwinds are over 7 MPH.  Granted, I tow pretty fast around 70-72 MPH.  But I expected more out of the big gasser.  I know it's not a diesel, but I figured it'd race up the grades my old 5.3L did at 4500 RPM down around 3000 RPM or so.  Climbing the Mogollon Rim in AZ, this was not the case.  Maybe closer to 4500 RPM vs 4000 RPM.  Maybe I just had a really strong 5.3!

 

The chassis is great, and so is the tech.  The truck is certainly more composed than the half ton was handling-wise, and I barely run any weight distribution at all, which improves the ride.  It gets about 1 MPG better than the Denali did towing, but it's an absolute thirsty pig not towing.

 

I'm still happy with the decision.  I don't mind the sound of a V8 doing work, and the transmission stays cool even in AZ.  Just expected a bit more jam.  Feels like GM left a ton on the table with this engine.

I’ve read a lot of lackluster reviews on the new combo and have seen an alarming number of issues with the 24. It’s not really a “new” model so not sure why it would be having so many growing pains?

 

lots of comments stating things like “my 20-23 was great or plenty good “ etc. 

 

 

[diyer2]

Just curious, what gear ratio is your truck? 

[Pryme]

3 hours ago, diyer2 said:

Just curious, what gear ratio is your truck? 

Aren’t all gas HD trucks 3.73? 

[UWSkier]

9 hours ago, diyer2 said:

Just curious, what gear ratio is your truck? 

3.73

[UWSkier]

14 hours ago, Pryme said:

I’ve read a lot of lackluster reviews on the new combo and have seen an alarming number of issues with the 24. It’s not really a “new” model so not sure why it would be having so many growing pains?

 

lots of comments stating things like “my 20-23 was great or plenty good “ etc. 

 

 

All new electrical architecture on several components.

I have the trailer brake/solar issue, which annoys me greatly, but everything else electronically has been OK so far.  I did have one instance where my driver's side blindspot monitor was seeing ghosts, but that resolved on its own on the next time out.

 

Things I thought I'd like but am somewhat disappointed in:

• Trailering electronics: I needed to buy a stupid pigtail for the 7 way so my cameras would work because GM can't just supply a steady 12v to the lights for some dumb reason.
• Engine power: I guess it's a punched out 6.2 basically, and that engine likes to rev too, so I shouldn't be surprised by the weak low RPM power.  I had about a 12 MPH crossing headwind in the grassy plains of NE Colorado today and it wouldn't shift past 7th gear and would drop to 6th and rev about 3250 RPM at the slightest incline running 68-70 MPH.
• Transmission gear spacing.  It goes from 8th to 6th far too often when towing.  I don't need 5 gears below 6th but I would love another one between 6th and 8th.
• Adaptive cruise for towing: I thought I'd like this, but it's really not very useful at all.  You'll be tooling along at 70 MPH or so with your cruise on and someone will pass you, then do the right thing and get out of the passing lane, but if they are only going 3-5 MPH faster than you, when they pull in front of you, the cruise hits the brakes.  This always seems to happen at the bottom of a hill you're about to climb.  After using it for about a thousand miles on the way east last month, I disabled it and am using regular cruise.
• Touch screen lag and sensitivity when using Android Auto.  Seems like you need to long press each location to get a response when trying to play a text or play/pause music.

Things I really like:

• The cameras.  I don't use the transparent trailer since I already have a Haloview with a mirror-mounted display, but the built-in cameras are awesome.  The trailer blind spot camera has come in handy dozens of times.  Flip on the indicator, look at the blind spot cam, then the haloview cam.  If it's the same vehicle in both, clear to move over.  The hitch cam is excellent for hooking up.
• Wireless Android Auto.  Nice to not have a cable.
• Wireless charging.  I had this on my old truck but the pad was too small for modern phones.
• The handling when towing.  I did all the mods I could to make the half ton tow well, but this tows better.
• Rubber floor liners.  I have a Golden Retriever.  'nuff said.
• The power tailgate. I dig being able to push a button and walk away, or use the keyfob to raise or lower.  The DW loves this feature too.

[the wanderer]

The 6.6 is not a diesel, and it's not a turbo. It actually puts out less power than the 6.2 does, and its in a much bigger and heavier truck. It's absolutely going to rev high when its working, just like every other N/A gasser in existence.

 

If you just wanted more towing power than your old 5.3, the 6.2 or 3.0 diesel would be the natural upgrade.

 

But as you noted, the 2500 platform itself is really a whole different truck, and the 6.6 is a cast iron block with much stronger internals, it will take a bigger beating every day without any issue. The 5.3 and 6.2 are aluminum blocks, not really meant for daily abuse.

 

If you want to compare apples to apples, check out "automotiv inc" on YT where he puts the 6.6 vs the Ford 7.3, you'll see they both rev very high when working hard, and the 6.6 actually goes up the eisenhower quicker though the Ford was running with damaged lifters/cam so there's that.

[Pryme]

9 hours ago, UWSkier said:

All new electrical architecture on several components.

I have the trailer brake/solar issue, which annoys me greatly, but everything else electronically has been OK so far.  I did have one instance where my driver's side blindspot monitor was seeing ghosts, but that resolved on its own on the next time out.

 

Things I thought I'd like but am somewhat disappointed in:

• Trailering electronics: I needed to buy a stupid pigtail for the 7 way so my cameras would work because GM can't just supply a steady 12v to the lights for some dumb reason.
• Engine power: I guess it's a punched out 6.2 basically, and that engine likes to rev too, so I shouldn't be surprised by the weak low RPM power.  I had about a 12 MPH crossing headwind in the grassy plains of NE Colorado today and it wouldn't shift past 7th gear and would drop to 6th and rev about 3250 RPM at the slightest incline running 68-70 MPH.
• Transmission gear spacing.  It goes from 8th to 6th far too often when towing.  I don't need 5 gears below 6th but I would love another one between 6th and 8th.
• Adaptive cruise for towing: I thought I'd like this, but it's really not very useful at all.  You'll be tooling along at 70 MPH or so with your cruise on and someone will pass you, then do the right thing and get out of the passing lane, but if they are only going 3-5 MPH faster than you, when they pull in front of you, the cruise hits the brakes.  This always seems to happen at the bottom of a hill you're about to climb.  After using it for about a thousand miles on the way east last month, I disabled it and am using regular cruise.
• Touch screen lag and sensitivity when using Android Auto.  Seems like you need to long press each location to get a response when trying to play a text or play/pause music.

Things I really like:

• The cameras.  I don't use the transparent trailer since I already have a Haloview with a mirror-mounted display, but the built-in cameras are awesome.  The trailer blind spot camera has come in handy dozens of times.  Flip on the indicator, look at the blind spot cam, then the haloview cam.  If it's the same vehicle in both, clear to move over.  The hitch cam is excellent for hooking up.
• Wireless Android Auto.  Nice to not have a cable.
• Wireless charging.  I had this on my old truck but the pad was too small for modern phones.
• The handling when towing.  I did all the mods I could to make the half ton tow well, but this tows better.
• Rubber floor liners.  I have a Golden Retriever.  'nuff said.
• The power tailgate. I dig being able to push a button and walk away, or use the keyfob to raise or lower.  The DW loves this feature too.

Nice write up. The adaptive cruise scenario is exactly why I don’t use it in my daily driver. It’s so annoying. A car slides back in front of you and your car hits the brakes. Also if someone you’re coming up on is going ever so slightly slower, your vehicle will slow slightly and before you know it you’re going 4-5 under the limit ha. 
 

why does the truck skip 7th? You said you would like something between 6-8. 

[UWSkier]

43 minutes ago, the wanderer said:

The 6.6 is not a diesel, and it's not a turbo. It actually puts out less power than the 6.2 does, and its in a much bigger and heavier truck. It's absolutely going to rev high when its working, just like every other N/A gasser in existence.

 

If you just wanted more towing power than your old 5.3, the 6.2 or 3.0 diesel would be the natural upgrade.

 

But as you noted, the 2500 platform itself is really a whole different truck, and the 6.6 is a cast iron block with much stronger internals, it will take a bigger beating every day without any issue. The 5.3 and 6.2 are aluminum blocks, not really meant for daily abuse.

 

If you want to compare apples to apples, check out "automotiv inc" on YT where he puts the 6.6 vs the Ford 7.3, you'll see they both rev very high when working hard, and the 6.6 actually goes up the eisenhower quicker though the Ford was running with damaged lifters/cam so there's that.

True, but my priority when shopping was to get something with excessive payload and increased safety margin when towing in the mountains and needing to stop, swerve, etc.  The HD blows away the half tons in that regard.  And that's why I'm happy with the truck overall.  It meets the primary objective in spades.

 

35 minutes ago, Pryme said:

Nice write up. The adaptive cruise scenario is exactly why I don’t use it in my daily driver. It’s so annoying. A car slides back in front of you and your car hits the brakes. Also if someone you’re coming up on is going ever so slightly slower, your vehicle will slow slightly and before you know it you’re going 4-5 under the limit ha. 
 

why does the truck skip 7th? You said you would like something between 6-8. 

Running roughly 70 MPH, 8th gear is around 2250 RPM.  7th is just around 2600 RPM.  6th is 3250 RPM.  Just my seat of the pants feel, but it feels like the engine would be happy around 2900-3000 RPM for the times it drops to 6th.  The reason I say that is if you are using cruise, on an incline, you lose MPH in 8th, and in 7th, but it accelerates right back up to set speed in 6th.

Edited August 11, 2023 by UWSkier

[Pryme]

8 minutes ago, UWSkier said:

True, but my priority when shopping was to get something with excessive payload and increased safety margin when towing in the mountains and needing to stop, swerve, etc.  The HD blows away the half tons in that regard.  And that's why I'm happy with the truck overall.  It meets the primary objective in spades.

 

Running roughly 70 MPH, 8th gear is around 2250 RPM.  7th is just around 2600 RPM.  6th is 3250 RPM.  Just my seat of the pants feel, but it feels like the engine would be happy around 2900-3000 RPM for the times it drops to 6th.  The reason I say that is if you are using cruise, on an incline, you lose MPH in 8th, and in 7th, but it accelerates right back up to set speed in 6th.

Will it not cruise in 9-10 unloaded? I find it odd they didn’t do more with 4 extra gears when top gear rpm is concerned. You would think it would loaf around 1,550-1,600 rpm at 70 but I’ve seen that’s not the case. 

[Grumpy Bear]

1 hour ago, UWSkier said:

Running roughly 70 MPH, 8th gear is around 2250 RPM.  7th is just around 2600 RPM.  6th is 3250 RPM.  Just my seat of the pants feel, but it feels like the engine would be happy around 2900-3000 RPM for the times it drops to 6th.  The reason I say that is if you are using cruise, on an incline, you lose MPH in 8th, and in 7th, but it accelerates right back up to set speed in 6th.

 

NA gas motors are always going to fall into the class of 'managed expectations". When towing at a set speed torque, not horsepower, is doing the work. When it slows down it does not have enough torque to hold that request so it increases its mechanical advantage by a gear change, multiplying the torque, and will do so until there is enough axle torque to manage that speed with a bit of excess to spare. 

 

Could it do this with more throttle in a hgher gear? Perhaps. But that method relies on increased cylinder pressure (load) which has its own problems when reliability and fuel economy are a concern and they both are. That motor is less stressed at 3,000 rpm at partial throttle that it is at 2,200 at WOT. 

 

 

[UWSkier]

2 hours ago, Pryme said:

Will it not cruise in 9-10 unloaded? I find it odd they didn’t do more with 4 extra gears when top gear rpm is concerned. You would think it would loaf around 1,550-1,600 rpm at 70 but I’ve seen that’s not the case. 

unloaded it'll cruise in 9-10 no problem.  It'll cruise at 75 MPH towing my ski boat in 9 no problem.  The travel trailer has the aerodynamics of a container ship is the problem...

[newdude]

On 8/9/2023 at 7:02 PM, UWSkier said:

We're about 3200 miles into a 4000 mile round trip from Arizona to WI and back via Colorado.  I did this trip last year in my 2016 Denali half ton with the 5.3L and 8 speed for comparison.

 

I'd say the Allison and 6.6 gas combo is "just OK."  It REALLY loves to drop down into 6th gear and rev to about 3250-3500 RPM on almost any hill, and it struggles to stay in 8th gear on the flats if the headwinds are over 7 MPH.  Granted, I tow pretty fast around 70-72 MPH.  But I expected more out of the big gasser. 

 

 

Sounds like its working as intended.  The 6 speed HDs would spin way more RPM in your scenario most likely.  

 

6.6 Diesel is the only step up here if towing fast is a goal.  

 

Also also.  1/2 ton ~ 5500lbs, HD crew cab gas ~ 7000lbs.  

Edited August 11, 2023 by newdude

[UWSkier]

Back home having towed around 4600 miles with the new 6.6L/Allison combo.

 

The comments I've made so far still hold true.  I expected a bit more power in the hills, but the biggest learning of the last 1000 miles or so is that the cruise control on the 2024 is not well suited to towing with this engine/transmission combo.  It absolutely abuses the drivetrain.  Driving through CO, NM, and AZ, I started driving manually in the big hills and it worked much better with less screaming high RPM.

[Doodle]

Great comments and feedback.  I have not towed with my 24 much yet, but I actually do like the transmission compared to the 23 6 speed I traded in.  In my opinion the two transmissions are totally opposite.  The Allison gets a heavy load moving easier, but seems to get real busy once up to cruising speed.   The 6 speed was doggy to me getting started but would hold power better once up to speed IMO.  With the 6 speed i generally never saw it shift much out of fifth with a load, the 10 speed will shift all the time and I really don’t know what gear it’s in.   But the Allison does perform well, it’s just a different driving experience.  The Allison is butter smooth so if you aren’t paying attention to the rpm’s you really don’t know it’s shifting much.  I would not fear pulling up to 26K in my area with the gas, its just mileage is gonna be 6-7.  I still have a 2015 LML so most of the time under heavy tows I’ll just use it but the 6.6 gas can do it.  I do feel like GM left some on the table with this engine.  I know whipple came out with a new supercharger, but it’s like $7500 so that make no sense, might as well get the diesel.