harsh ride 2009 yukon denali

[6.2regcab]

Hi

I have very serious problem that can't be solved at any dealer .Bought a used 2009 Yukon denali which have a very rough ride . Sense one year now every month I change parts and still its same rough ride .Here's what happen I can feel ever slight bump in the road and if I hit a pothole the whole truck shake.i test drive 6 Yukon denali's up to now and its totally different ride ,there very smooth even if you hit a pothole nothing happen you barely feel it in the cab .Now the things that I change :

1: tires replaced and balanced 2 times + checked for bent rims .

2: replaced front shocks .With same GM replacement .

3:replaced all ball joints and bushing in front suspension . All GM oem

4: 3 dealers checked it and told me to sell the truck or live with it or take it to another dealer .

The only thing which not replaced is the front springs which all dealers told me that they are OK and never saw them fail ,

what should I do Im very dispirit and I don't want to sell it after all these thing replaced .

Please someone help me

[fondupot]

What about the rear shocks and springs?

[Doug_Scott]

Reason dealer said they have never seen springs fail is because springs do not become a higher spring rate with age. Do you know if the springs have ever been replaced?

You could try measuring the height of the front bumper, and compare it the height of the front bumper on another 09 Yukon Denali that you know has stock suspension in it.

Same for rear.

 

About the only thing that can cause a rough ride like described is a modified suspension. Look for aftermarket bushings in all suspension mounting points, including anti-sway bar. Look for signs of springs being changed. Springs may have labels on them to help identify them. Denali's usually have some form of special suspension don't they? Did your truck come with Auto-Ride? Has someone replaced the Auto-Ride with non Auto-Ride parts?

[6.2regcab]

its auto ride with rpo z55

i checked there is no modification to the suspension all new gm oem parts

[Doug_Scott]

I have never seen Auto Ride, so bear with the stupid questions. Does Auto Ride have different settings you can try? Can you alter the height of the vehicle manually? What have you tried in regards to auto ride settings? Please don't just say "I tried everything", some of us have no idea what everything is.

[6.2regcab]

auto ride is like magnatic syspension in front and air at the back to level the rear of the truck

hmmmmm i tried mean i changed every thing in the truck nothing fixed it

[Jsdirt]

Electronic suspension. Fan-friggin-tastic .......

[6.2regcab]

is there a part no. on springs to check them

[Doug_Scott]

What size tire and rim? What brand model tire, and if you know, what load range(as in are these LT type tires). Does it have the magnetic suspension? Take a look at the bump stops on all 4 corners. Look for contact marks on them. Not normal to hit them in normal day to day driving.

 

And again, bear with me, still no first hand knowledge, does your truck have "normal" springs? Can the shocks be removed, and still be able to drive the truck? If you can, you can rule out the shocks if the ride is still very harsh. If ride becomes very soft and bouncy, issue is likely in the shocks. I saw a kit earlier that replaces all the air-ride stuff completely and replaces it with normal shocks and springs. I cannot find that link from this machine, it will be in my history on other machine. I will locate it and post it here later in the day.

[6.2regcab]

20" oem size ,changed from Goodyear to Michelin dont know the load range . yes its magnetic ride . I cant remove the shocks .also the bump stops never hit as I think . my problem is that I feel each movement in front suspension and if I hit a pothole the truck shakes . Im thinking that the previous owner have changed springs to none magnetic ride springs but dont want to lose more money on new springs cause they look the same to me .

[6.2regcab]

Any GM guys here to help me out .

[00Silverado4x4]

Did you figure out the load range of the tires and what pressure is in them? If you have a higher load range and running higher pressures you will definitely have a rougher ride.

[Doug_Scott]

20" oem size ,changed from Goodyear to Michelin dont know the load range . yes its magnetic ride . I cant remove the shocks .also the bump stops never hit as I think . my problem is that I feel each movement in front suspension and if I hit a pothole the truck shakes . Im thinking that the previous owner have changed springs to none magnetic ride springs but dont want to lose more money on new springs cause they look the same to me .

 

From what I can find about the Auto-Ride, you should have an option to set suspension to Tow/Haul or normal. Does that switch make any difference?

 

To make sure that we are talking about the same thing, harshness is like you can feel it when you run over even the slightest unevenness in road surface(like you can not only tell you ran over a dime on the road, you can tell what year it was), and rough ride is like there is no suspension at all. You hit a bump and it is like you have no suspension. Harshness is for small movements in suspension, roughness is large movements in suspension.

 

There are more parts that can affect the ride quality in regards to harshness, compared to roughness.. Higher rate springs will not necessarily cause a harsh ride, but can cause rough ride. Parts that can make the ride harsh include control arm bushings(polyurethane instead of rubber), sway bar bushings, shock absorbers, tire type("LT" instead of "P"), tire pressures, tire profile, and air pressure in tires

 

I once had a car come in for harsh ride that ended up being caused by another garage that had replaced front springs in the car, and for some reason they had removed the lower control arms to replace springs. When they put it back together they tightened all bolts back up with the suspension hanging. This caused the lower control arm bushings to be loaded when the wheels were back on the ground. Control arm bushings have a rubber core that is attached to the outside of the bushing, as well as the sleeve that the bolt goes through. When you tighten the control arm with tire off the ground, then put it back on the ground, the rubber in the bushing twists up, making the bushing resist more suspension compression movement. Simply loosening the lower control arm, then re-torqueing it with wheels on ground fixed it. It also would have resolved itself if left alone, but that would also have broken the rubber attachment to the sleeve.

[6.2regcab]

thanks guys for the replays.

- yes 06SierraZ71 load range is for passenger cars .and running at 32 psi by door sill sticker .

-doug_scott I tried tow/haul it make it jumpy a little bit than normal no difference in ride. My ride is rough and harsh .I filmed a small vid and post it in youtube

I hit small bump in the road and the whole truck vibrate .

 

 

 

I think its an input to suspension module that giving wrong reading like yaw sensor ,but don't what voltage reading should it have for minimum .

[Doug_Scott]

Is there a fuse that you can remove to disable the magnetic ride altogether? Or maybe unplug the front shocks and go for a drive? I expect it will set a code doing that, but, perhaps the shocks have a soft ride by default, and taking power away or unplugging the shocks may leave the shocks in the softest setting. Doing this will not tell what is wrong, but may tell you that you are on the right path.