Z55 Oem replacement done- still rough ride?

[Denaliz]

Hey guys,

On my 2011 Yukon Denali -i just wrapped up replacing my z55 front struts, (entire coilover assembly,all parts including springs) as well as my rear shocks last summer. Front is oem ac delco/gm, rear was the Arnott rebuild ones. Confirming this is not a passive conversion but a full z55 replacement of all 4 corners.

I’ve had the front end parts all replaced as well (bushings, end links, inner/outer tie rods, control arms, ball joints.. etc) and upgraded to Eibach sway bars.

I’m not throwing any codes , compressor runs and turns on with no issues that I can see, but the ride is still for shit imo. I’m the original owner and absolutely know what it’s supposed to feel like but I’m baffled here lol..

All 4 tires all new as well. The only thing I can possibly think of is the garage that handled the install of the front ac delco 580-434/ GM# 19300039 the part# has changed over the years ) coilover struts, may not have recalibrated the suspension system in the ecm? I’m going to have it hooked up tomorrow and checked with tech 2.

Anyone have any thoughts or suggestions?

 

[George B]

I can’t find that front strut part number anywhere.

 

[Denaliz]

Typo/ corrected- thx I missed that . The point I was making is it’s not a parts issue an aftermarket or passive- gm replacement ac delco parts were used with correct rpo codes(my phone keyboard hates me.. )

 

[gooffeyguy]

How did the ride feel before you replaced all the shocks/struts, and for how long?

 

[George B]

Did I read right that you changed the springs too? Can you post up a full parts list. Several guys here are really good at cross-reference.

 

[Denaliz]

How did the ride feel before you replaced all the shocks/struts, and for how long?

Felt worse with aging of the suspension system. It wasn’t a daily driver for last 4 years. once the rears were shot I replaced and front struts done a couple months ago when I finished refresh

 

[swathdiver]

Hey guys,

On my 2011 Yukon Denali -i just wrapped up replacing my z55 front struts, (entire coilover assembly,all parts including springs) as well as my rear shocks last summer. Front is oem ac delco/gm, rear was the Arnott rebuild ones. Confirming this is not a passive conversion but a full z55 replacement of all 4 corners.

I’ve had the front end parts all replaced as well (bushings, end links, inner/outer tie rods, control arms, ball joints.. etc) and upgraded to Eibach sway bars.

I’m not throwing any codes , compressor runs and turns on with no issues that I can see, but the ride is still for shit imo. I’m the original owner and absolutely know what it’s supposed to feel like but I’m baffled here lol..

All 4 tires all new as well. The only thing I can possibly think of is the garage that handled the install of the front ac delco 580-434/ GM# 19300039 the part# has changed over the years ) coilover struts, may not have recalibrated the suspension system in the ecm? I’m going to have it hooked up tomorrow and checked with tech 2.

Anyone have any thoughts or suggestions?

19300039 is a valid number but it does not come up for a 2011 Yukon Denali. Look at your RPO Sheet for your 6XX and 7XX codes and then plug your VIN in here to verify:

https://parts-catalog.acdelco.com/acesCat.php?#

Now, when the struts were replaced, did they replace all of the ancillary parts too? This can definitely contribute to a poor ride as well. Definitely get the Tech-2 on it and let us know.

 

[gooffeyguy]

Maybe the controller is bad. I think @Joseph Garcia just recently had a problem with his suspension controller not working properly

 

[Joseph Garcia]

As @swathdiver suggested, a Tech 2 or equivalent is required to see what is actually going on within the suspension's electronic components. Without that, you are simply groping in the dark. No adjustments or reprogramming are required for the ECM for a simple replacement of Z55 components with new Z55 components. No adjustments or reprogramming are required for the ESCM for a simple replacement of Z55 components with new Z55 components. However, since the coil springs were replaced in the front struts (complete new struts), I would recommend a recalibration of the Auto Level Control (ALC) in the ESCM, as the ride height in the front may have changed with the new coil springs, and a Tech 2 or equivalent is required for this procedure.

Perhaps, you can explain in greater detail what you mean when you say that "ride is still for shit imo", so that we can better understand what you mean by that. What in the suspension's ride characteristics is wrong or missing.

Also, when I replaced my front suspension on my '07, I was advised that GM no longer makes the front coil springs for the Z55 strut assembly, so I had to get alternate front coil springs when I built my front strut assemblies. Perhaps, GM still makes the front coil springs on the '11 model year, even though the '07 and the '11 are both NNBS bodies, though I would think that may be unlikely. So, I wonder about the claim that the front strut assemblies are "oem ac delco/gm".

The Eibach sway bar installation will definitely affect the ride of the truck, but it should not be in a negative way. My Hellwig sway bar installation definitely impacted the ride in my truck, but again, not in a negative way. However, the Hellwig sway bars definitely reduced the amount of second-to-second shock/strut electronic dampening changes required from the ESCM as monitored by my Tech 2 in real time, as the Hellwig sway bars managed much more of the roll prevention while driving.

 

[Denaliz]

The gm coil springs are discontinued so I went with a moog aftermarket designed for my year and make.

Yes the entire coil over assembly with all gm parts we’re used excluding the moog springs and strut mount which was oem aftermarket. My new struts and shocks are actually under warranty from AcDelco and Arnott for the rears.

Usually you’d throw a code I assumed but I’ll make time and have it hooked up to tech 2 to go thru the motions.

 

[ivin74]

Hey guys,

On my 2011 Yukon Denali -i just wrapped up replacing my z55 front struts, (entire coilover assembly,all parts including springs) as well as my rear shocks last summer. Front is oem ac delco/gm, rear was the Arnott rebuild ones. Confirming this is not a passive conversion but a full z55 replacement of all 4 corners.

I’ve had the front end parts all replaced as well (bushings, end links, inner/outer tie rods, control arms, ball joints.. etc) and upgraded to Eibach sway bars.

I’m not throwing any codes , compressor runs and turns on with no issues that I can see, but the ride is still for shit imo. I’m the original owner and absolutely know what it’s supposed to feel like but I’m baffled here lol..

All 4 tires all new as well. The only thing I can possibly think of is the garage that handled the install of the front ac delco 580-434/ GM# 19300039 the part# has changed over the years ) coilover struts, may not have recalibrated the suspension system in the ecm? I’m going to have it hooked up tomorrow and checked with tech 2.

Anyone have any thoughts or suggestions?

You need to get the air ride suspension read by a GM Tech 2 scan tool. Not all scan tools can read suspension codes.
Several years ago my SUV rode rough (hard) and that's after replacing all the parts with OEM components. In my case, the steering angle position sensor was the cause. When the steering position sensor malfunctions it causes the shocks to tighten up. Good luck

 

[CharlieBrown6]

You need to get the air ride suspension read by a GM Tech 2 scan tool. Not all scan tools can read suspension codes.
Several years ago my SUV rode rough (hard) and that's after replacing all the parts with OEM components. In my case, the steering angle position sensor was the cause. When the steering position sensor malfunctions it causes the shocks to tighten up. Good luck

When your steering position sensor malfunctioned did it throw a code? Our 2011 Denali has been riding rough for awhile and I'm starting to wonder if this might be the case.. I do have a tech2 scanner, how can I check this?

 

[ivin74]

When your steering position sensor malfunctioned did it throw a code? Our 2011 Denali has been riding rough for awhile and I'm starting to wonder if this might be the case.. I do have a tech2 scanner, how can I check this?

No, the only thing I got was service stability or something like that on the DIC. Once I connected the Tech2 I read the code. I don't remember under what function It was under though.

@CharlieBrown6
Update, I read the code under the ESC screens.

 

[S1W99]

Did you find a solution? I have a 2012 LT with new Mevotech kit, Acdelco OE struts 4600 Bilstein rear shocks. Ride is OK but not soft or comfortable. No roll and stiffer but still harsh over slower bumps in there neighborhood.

Thanks

 

[S1W99]

Did you figure out what was causing the rough ride

 

[Denaliz]

Yes- somehow my new front left strut locked up? It was pretty quick For that to happen.

Ended up having the new coilover assembly removed and new ac delco strut installed. Ac delco did warranty out the strut but I still had to pay for a shop to remove and install.

 

[Denaliz]

So I’m truly baffled here on this a year later. On my Z55 suspension-I had 3x front struts lockup after replacing both coil over struts and assemblies last year.

I used the same oem GM ACDelco #580-434- there was no conversion of anything.

1st/1 of them locked up shortly after the install and I assumed it was just bad luck. Did a warranty exchange and went down the road.

Fast forward a year later -My suspensions been riding rough again and I don’t drive this thing daily either. The shop I had look at the suspension, confirm if the alc trim reset needed to be done, check height sensors and control modules.

Called me next day and said both front struts locked up. This is absolutely insane to me to happen again only 12 months or so later.

The entire coilover assembly was replaced with oem gm parts excluding the strut mount which I ordered thru amazon for 22 bucks each. They’re just stamped metal to my eye and they matched up perfectly so I thought shouldn’t be an issue?

I decided to go ahead and bite the bullet and by new oem acdelco ones for 100 each to remove any doubt of an inferior aftermarket strut mount causing issues this time.

My question after the brief ramble is has anyone heard of Z55 front struts locking up so soon after an oem replacement?

I couldn’t find anything online but I’m beyond puzzled to what’s going on here

 

[Geotrash]

So I’m truly baffled here on this a year later. On my Z55 suspension-I had 3x front struts lockup after replacing both coil over struts and assemblies last year.

I used the same oem GM ACDelco #580-434- there was no conversion of anything.

1st/1 of them locked up shortly after the install and I assumed it was just bad luck. Did a warranty exchange and went down the road.

Fast forward a year later -My suspensions been riding rough again and I don’t drive this thing daily either. The shop I had look at the suspension, confirm if the alc trim reset needed to be done, check height sensors and control modules.

Called me next day and said both front struts locked up. This is absolutely insane to me to happen again only 12 months or so later.

The entire coilover assembly was replaced with oem gm parts excluding the strut mount which I ordered thru amazon for 22 bucks each. They’re just stamped metal to my eye and they matched up perfectly so I thought shouldn’t be an issue?

I decided to go ahead and bite the bullet and by new oem acdelco ones for 100 each to remove any doubt of an inferior aftermarket strut mount causing issues this time.

My question after the brief ramble is has anyone heard of Z55 front struts locking up so soon after an oem replacement?

I couldn’t find anything online but I’m beyond puzzled to what’s going on here

First I've heard of this and I've been around here a while. Both of my rigs are still rolling on the originals up front. My 2007 has 227K on it and my 2012 has 132K. I can't imagine that the mount would be a factor, but the shocks are pretty sophisticated components, so it may be.

 

[Denaliz]

Same here- I bought my Denali new over Thanksgiving 2010. I just can’t figure out what it could be so eliminating the cheap amazon strut mount since I’ll be having both oem acdelco struts replaced.

No codes are being thrown but I kind of want to have the escm tested maybe?