2019 GMC AT4 w. empty trailer bottoming out!

[Jack D]

 

On 4/4/2019 at 6:29 PM, 21STCMC said:

Brand new 2019 AT4 with 6.2 and 10 speed, hooked up my 24' ATC aluminum trailer before I put my car in it and it bottoms out on the bump stops,

just put my 2945 lb race car in and the truck, now sagging in the back so bad I had to change receptor and ball out just to release the jack on the trailer 

Drove it around the block and it steers like crap due to the suspension being bottomed out

This truck supposedly has 9k plus towing capacity? 

 

My 2015 Suburban w. 5.3 is perfectly level when towing the exact same load

 

Anyone with same towing problems?

Are you using a weight distributing hitch with equalizer/spring bars? If not, you should be, and there's the answer to your problem. Any half-ton towing anything over 3000 - 3500 lbs. should be using a weight distribution setup. The equalizer bars act as a set of leaf springs between the truck and trailer, evenly distributing the weight, and equalizing ride height.

 

I doubt that it's a  problem with your springs or shocks. Was your Suburban a 2500 series by any chance (sounds like it if the hitch receiver was higher than on your AT4)?

 

My trailer's GVWR is only 6500 lbs. but tongue weight is close to 1000 lbs, requiring me to use a weight-distributing hitch rated for 10,000 lb. total/1,000 lb. tongue. Without that, I'd have the same issue that you have. Your manual has trailering tips.

 

You should distribute weight on the trailer so that the tongue weight is 10-15% of the total weight of the fully loaded trailer. Weight distribution hitches can be purchased in weight increments, and your hitch rating should exceed the trailers GVWR and tongue weight, so that you have a safety cushion. Any hitch shop or RV dealer should be able to set you up with a proper hitch. 

 

 

[21STCMC]

15 minutes ago, Jack D said:

 

Are you using a weight distributing hitch with equalizer/spring bars? If not, you should be, and there's the answer to your problem. Any half-ton towing anything over 3000 - 3500 lbs. should be using a weight distribution setup. The equalizer bars act as a set of leaf springs between the truck and trailer, evenly distributing the weight, and equalizing ride height.

 

I doubt that it's a  problem with your springs or shocks. Was your Suburban a 2500 series by any chance (sounds like it if the hitch receiver was higher than on your AT4)?

 

My trailer's GVWR is only 6500 lbs. but tongue weight is close to 1000 lbs, requiring me to use a weight-distributing hitch rated for 10,000 lb. total/1,000 lb. tongue. Without that, I'd have the same issue that you have. Your manual has trailering tips.

 

You should distribute weight on the trailer so that the tongue weight is 10-15% of the total weight of the fully loaded trailer. Weight distribution hitches can be purchased in weight increments, and your hitch rating should exceed the trailers GVWR and tongue weight, so that you have a safety cushion. Any hitch shop or RV dealer should be able to set you up with a proper hitch. 

 

 

Thanks for the replies!

The empty ATC trailer  (3642lbs) with the proper hitch receptacle height still has the suspension on the bump stop when the trailer is empty,

my 2015 Suburban (1/2 ton w. 5.3) will not hit the bump stop unless the trailer is loaded and then only on bumps.

After research I should have gotten a Max tow package but unfortunately not avail on AT4 or Denali,

pretty sure the issue is from the cheap off road shocks and the springs. 

I incorrectly assumed the truck would have more towing capacity in the suspension than a half ton 5.3 Suburban

 

My dealer has agreed to take the truck back in trade so it looks like my choices are:

1) Keep the AT4 and look at a load leveling hitch, air bags, shocks, springs or a combination of those

2) Get a Denali and hope the Denali's adaptive ride shocks will adjust enough with the trailer to keep it off the bump stops

3) Get a SLT with a max tow package (will lose the color matched bumpers and quite a few other features) and cost is the sam

4) Get a 2019 2500 which is more money, not as user friendly around town, harsher ride and more $$ 

 

I have to do something pretty quick to take advantage of the dealer's generous offer to take the truck back

[eppieguy]

Just get air bags and be done. Will be a lot cheaper than trading in on a new truck.

 

Just my .02

[Rsktm300xcw]

I have a 2019 at4 and it tows my 4 place snowmobile trailer with no suspension issues at all. Wiring and light issues are another story not for this thread. Shocks do not affect ride height. They are there as dampers which slow down the stroke of the suspension through its travel. You must have excessive tongue weight or defective springs if you are bottoming out just driving down the road. TFL does some really good towing tests with half ton trucks and explains how much tongue weight your truck should be able to handle according to the stickers in your door jamb. You should check it out. In the meantime maybe post I picture of your trailer hooked up to your truck. A lot of pretty savvy people on here might pick up on something. The guys at TFL Truck regularly tow 7000 to 9000 pounds with half ton trucks in their tests.

[amxguy1970]

On 4/5/2019 at 1:39 PM, Sierra Dan said:

Your problem is related to the less than optimum factory Tenneco "Rancho" shocks. 

A shock improvement or airbag setup will help yield better towing results. 

This is why people need to vet the information from others carefully because of false information, such as your comments about "Tenneco" Rancho shocks being related to his sag. His truck not holding the load has almost nothing to do with the shocks and everything to do with the springs or how he is actually loading the truck/trailer. The shocks are not holding the weight and have very little to zero to do with sag and support of the trailer weight (a new stiffer shock may save a millimeter or two of height if it even registers), the springs are what determines height and stiffness. The shocks are fine, the OP could go spend $4k on a new set of top of the line King shocks and bolt them up and it would sag the same (excluding the coil springs they usually come with). Shocks control movement, not hold loads, that is what the spring is for. How am I not surprised you then tell him to go buy "ThyssenKrupp" Bilsteins? Honestly, do you work for them or something? The OP can put your golden fairy dust shocks on and it will sag the exact same.

 

OP, take the truck to the dealer, something is not right. Something is broken if it is sagging like you say. Also be weary of what people state online and do your homework and plenty of research, there are a ton of clueless people out there as you can see...

 

Tyler

[amxguy1970]

1 hour ago, Rsktm300xcw said:

I have a 2019 at4 and it tows my 4 place snowmobile trailer with no suspension issues at all. Wiring and light issues are another story not for this thread. Shocks do not affect ride height. They are there as dampers which slow down the stroke of the suspension through its travel. You must have excessive tongue weight or defective springs if you are bottoming out just driving down the road. TFL does some really good towing tests with half ton trucks and explains how much tongue weight your truck should be able to handle according to the stickers in your door jamb. You should check it out. In the meantime maybe post I picture of your trailer hooked up to your truck. A lot of pretty savvy people on here might pick up on something. The guys at TFL Truck regularly tow 7000 to 9000 pounds with half ton trucks in their tests.

 This all day is great advice.

 

OP, post a pic and let those that know see and make recommendations. Personally if it is sagging as you say something could be broke or you messed something up with this new truck and setup.

 

Tyler

[Limelight]

7 hours ago, MadCaddie said:

I'm gonna put an airlift kit in my AT4 on mine just because of ride quality and my plans to lift/level but I def don't need it.  

 

It doesn't even squat a little when I put my 18ft flatbed on there and that's got to weigh close to the same as your atc.  I've hauled a 4 place loaded with sleds and gear and it simply leveled the truck out. 

 

Sounds like something else is wrong to me.. 

I have an ARB fridge and a swing away toolbox in my bed (I guess around 100# for both) and I am now totally level. Springs are soft I guess. 

LTZ Z71 CCSB

[Sierra Dan]

So Tyler...

Good to hear from you again.

I guess you missed the part of my post that also advised the OP to check into an airbag setup?

If shocks do not have much of an effect on towing, why does GM offer a special absorber with specific tuning set with the max trailering package?

Why not include the Rancho on all option packages?

Why does Ford not offer the Raptor with Ranchos?

Some like their Ranchos, most do not according to the poll I created.

I rest my case.

OP, sorry if i steered you in the wrong direction.

 

 

[Limelight]

14 minutes ago, Sierra Dan said:

So Tyler...

Good to hear from you again.

I guess you missed the part of my post that also advised the OP to check into an airbag setup?

If shocks do not have much of an effect on towing, why does GM offer a special absorber with specific tuning set with the max trailering package?

Why not include the Rancho on all option packages?

Why does Ford not offer the Raptor with Ranchos?

Some like their Ranchos, most do not according to the poll I created.

I rest my case.

OP, sorry if i steered you in the wrong direction.

 

 

Airbags are a great suggestion.  

 

Shocks are more about control than weight holding- which is obviously the springs job. Stiffer springs will require more robust shocks to control the motion better. That’s why different shocks are specd for different packages- not to hold more weight. 

 

[dieselfan1]

I know what I would do.

Get a 2500 and don't look back.

Why add air bags or do a bunch of other shit when you could just hook it on the 3/4 ton and go.

Everyone always says a 3/4 ton is such a non user friendly truck around town. Other than less MPG's, its not that big of a deal. 

You would be better off in the long run. The 6 liter is proven.

I don't like living on the edge with too much trailer and not enough truck. It's up to you though.

[Imcrazy]

I'm not sure what is amiss but, I've had 12k (I know it was stupid) behind my 1500 and it wasn't on the bump stops and I don't have max tow... I was towing a tandem axle equipment trailer with a skid steer on the trailer... I'd get a WD hitch etc, it's not worth driving a 2500 hd around town all the time for the few times you need to trailer..

[Chevy sad]

Shock damping will greatly improve (reduce) trailer sway, but will not adjust ride height. If you trailer tongue height and hitch height are correct, when the suspension compressed past center or raise above center, it slightly accelerates the trailer making sway worse. Stiffer shocks slow the process increasing stability. I would get the part number off the rear springs and have the dealer check them. As someone mentioned above, ensure your hitch is the correct height. If you are using the same hitch as the Suburban then that may be part of the issue. That AT4 sits way higher. 

[21STCMC]

Thanks for the spirited discussion, looks like consensus is, there isn’t one.

 

i assure you that my Suburban receptacle is higher than the AT4, I had to remove the drop and install a straight one.

 

On the 2500, I have only owned one and it was a drw and a Royal pain to drive in the city and to park.

 

spoiled on pulling the trailer I have a Seneca that I normally pull it with but wanted something else to replace my Suburban as a daily but still be able to pull the trailer adequately without getting the RV out.

 

Included a couple of half ass pics but you can see it’s on the bump stop and this is with an aluminum trailer without my car loaded.

[Donnyb313]

16 minutes ago, 21STCMC said:

Thanks for the spirited discussion, looks like consensus is, there isn’t one.

 

i assure you that my Suburban receptacle is higher than the AT4, I had to remove the drop and install a straight one.

 

On the 2500, I have only owned one and it was a drw and a Royal pain to drive in the city and to park.

 

spoiled on pulling the trailer I have a Seneca that I normally pull it with but wanted something else to replace my Suburban as a daily but still be able to pull the trailer adequately without getting the RV out.

 

Included a couple of half ass pics but you can see it’s on the bump stop and this is with an aluminum trailer without my car loaded.

Looks like that could be the new carbon composite leaf spring on the bottom of the spring pack? 

[Rsktm300xcw]

In that picture it looks to me like there is either too much tongue weight or something is not right with your springs. I assume the trailer is empty in this picture like you said earlier. Did you check the sticker in the door jamb to see what the GVW is? I believe you can have a tongue weight of 10% of the GVW. So if the GVW is 9300 pounds the tongue weight can be 930 pounds. The trailer axles are supposed to carry the majority of the weight. If the tongue weight is too much or even too little the trailer starts to "drive" the truck.