2008 Yukon XL sagging with trailer

[scoutabout]

I've got a 2008 Yukon XL 4WD with 5.3L v8 with 90,000 miles. It has the auto leveling air suspension and I've had a few issues while towing. The system works fine under non-towing conditions. As soon as I hook up a trailer, the compressor kicks on and levels the rear end. I tow several trailer configurations including a 6000lb car hauler/vehicle combo, a 7000lb enclosed trailer and a 6500lb travel trailer. After a short time, the rear end squats to nearly the bump stops. Within 15 minutes the compressor gives up on trying to load the air shocks. I'm not overloading the tow capacity. I want better leveling and tow handling with this vehicle.

I've tried reading this forum and others and have learned a little. Hoping to get some real world opinions.

Questions

1) Is it likely the air shocks or lines are leaking?

2) Could I install a set of manually controlled helper air bags and keep the auto leveling system?

3) Should I remove the air system and convert to a standard suspension system and then install a set of helper air bags?

I don't need a diesel truck. I have one. I use the Yukon when I have to tow something AND I want to take my wife and four kids.

Any other opinions about getting better tow performance would be appreciated!

 

[Goodinblack]

I would not convert.

I would add airlift 1000s though

 

[yates ™]

What do you mean by "Within 15 minutes the compressor gives up on trying to load the air shocks"? Is there an error in the DIC? Pop a fuse? Restarting the truck restart the compressor? My best guess is the compressor is dying and putting out less output than it should and with a load on there it is unable to level the truck in the allotted time, there is also probably a leak somewhere.

 

[scoutabout]

I would not convert.

I would add airlift 1000s though

After a little more research, I think you are correct. I think I need to make sure the air ride system is working 100%.

What do you mean by "Within 15 minutes the compressor gives up on trying to load the air shocks"? Is there an error in the DIC? Pop a fuse? Restarting the truck restart the compressor? My best guess is the compressor is dying and putting out less output than it should and with a load on there it is unable to level the truck in the allotted time, there is also probably a leak somewhere.

It is weird. The compressor "stops trying". No error, no message, no indication. Shut off the truck for more than 30 minutes and it will restart and fill up the shocks. Then slowly go down.

I believe I have figured out my problem after reading more and writing my own question. You are both correct, there is likely a leak somewhere, the shocks might need to be replaced, and/or the compressor is faulty. I will fix the system and probably add some helper air bags. Looking at the Arnott stuff seems to be the way to go.

 

[yates ™]

Shouldn't need extra air bags, if there is a leak it could be enough that the compressor can keep up with added weight and shuts off as a protection. I figured it would give you an error but not familiar with factory air suspension.

---------- Post added at 04:43 PM ---------- Previous post was at 04:42 PM ----------

Make a soapy solution and heavily spray everything down and look for bubbles.

 

[snaward]

My 08 Yukon Denali started doing the same thing around 85K miles. When I would stop for gas or something it would level out, then slowly sag back down after the compressor timed out. I replaced the OEM rear shocks with Arnott's air bag shocks. You loose the active shock function, but you get a great warranty. Last trip towing a 6500lb trailer, no sagging, just like what it did originally. They are easy to replace and no warning or error lights on the dash after the installation.

 

[livingez_123]

Weight distribution bars will do wonders. The trailer will tow so much better and you air ride wont work overtime. I was towing my inlaws 25' travel trailer and the air ride kept it nice and level but I didn't like how it followed me around corners. So the next trip out I put on my WD bars and it was such a night and day difference. I have 2 sets of bars also. 1 is a 500lbs set and the other is a 1000lbs set. I use to transport RV's for over 20 years with a Dodge 3500 dually. The never needed the WD bars to keep the rear end up but I did use them on all of the trailers just because of how much better they pulled. just some food for thought.

 

[camarozz]

My 08 Yukon Denali started doing the same thing around 85K miles. When I would stop for gas or something it would level out, then slowly sag back down after the compressor timed out. I replaced the OEM rear shocks with Arnott's air bag shocks. You loose the active shock function, but you get a great warranty. Last trip towing a 6500lb trailer, no sagging, just like what it did originally. They are easy to replace and no warning or error lights on the dash after the installation.

I thought the replacement shocks have the active sensor on them? I was about to buy the whole system. Shocks and pump

 

[snaward]

I thought the replacement shocks have the active sensor on them? I was about to buy the whole system. Shocks and pump

Arnott's sells what they call passive and active. Their active version does not interface with the GM suspension control system and is apparently internally controlled. So far I have been real pleased and will change the fronts to Arnott's next. The GM rear leveling system controls the air compressor, so that portion of the GM system still works as the originally installed.


BTW - I agree with Livingez_123, WD bars are a must with 1/2 ton vehicles and are nice to have with 3/4 ton and above based on the towing I have done.

 

[TowGMC]

I'll also echo the need for WD system. And if you look at your hitch I believe that the tow rating for dead weight towing is just 5,000 lbs so you're far beyond what is approved by GM or is legal in most states.

If I try to tow my 6500 lb race trailer dead weight for more than just a few miles it hobby horses on every bump. And on the highway you can feel every movement of the trailer especially when passing 18 wheelers. And the air shocks can't level the Denali out with the 900 lb tongue weight I carry, plus the steering is very light feeling. But with the WD I level out the truck and trailer static before turning on the Denali, then the air shocks only have to pump up a small amount to keep it all level.

FWIW I use the Reese Dual Cam WD which incorporates the weight distributing capability with an integrated sway control. Extremely nice way to go. And I have 500, 800 and 1000 lb spring bars depending on what I'm towing, usually use the 1000 with the race car trailer when it's fully loaded.