Heavy duty rear shocks

[Erock7625]

Trying to make sense of what shocks I have and my replacement options on my 2011 Yukon XL SLT. I've been reading through threads here and from what I understand I have the ZW7 premium suspension that supposedly includes Nivomat self leveling shocks in the rear. I do not have the Z55 option and my other option codes are 6XU and 7XU whatever those mean. I'd like to get a more heavy duty shock, my Yukon has the tow package and when I load it up with a roof rack, full back area and a rear cargo holder it rides low in back and tends to bottom out when going over big bumps.

What are my options for rear shocks? I don't really want to add any lift just something that will handle the load better, When I go to rockauto most of the heavy duty options from Gabriel, Monroe and Rancho all say except Z55 or ZW7 suspension. Also is there anything else worth replacing back there like the stabilizer bar links?

Thanks!

 

[OR VietVet]

https://www.rockauto.com/en/moreinfo.php?pk=2567366&cc=1446828&jsn=878&jsn=878 is what it calls for at RA. I looked thru all options and at least at RA it gives no other options with the ZW7 RPO code. It is a self leveling system, according to the RPO code definition and therefore if you load it, it should not be bottoming out unless whatever you are putting in there or on there is beyond the system's capabilities. May need to customize a helper set up. Others here will likely chime in with more info.

Also, any add on help that you can do like beefier sway bar and links, go for it. I just ordered a front and rear Hellwig system for mine because as @Doubeleive said, the bars are bigger and solid instead of hollow.

By the way, the 6XU is the left front shock identification and the 7XU is the right front.

 

[Erock7625]

Thanks for the reply, so that shock looks like the standard daily driver replacement. Is it actually self leveling though, the zw7 is supposed to be Nivomat self leveling shocks and that ac delco 540-631 is only $56 so I don’t think that is a Nivomat shock.

The ones on there look fairly old, it’s possible they are just worn and putting new ones on will help handle the load better. Would replacing it with the 540-630 z71 off road shock or 540-640 z56 police pkg shock be a better heavy duty option although that might require new springs to match.

Also plugging my VIN into Monroes website they show this shock as fitting my vehicle, would it be better than the AC Delco shock?

Reflex Monotube Shock 911506 Premium - Limited Lifetime Warranty; Except Electronic Adjustable Suspension;

 

[OR VietVet]

The only reference I have is that ZW7 RPO code and that is why I put up that link. There will be other people here that can likely talk about the combination of shocks and maybe springs as well that will work fine. You also have to make the the shock mounts are the same and the shock length relatively close.

 

[Fless]

I assume your truck is a 1500. I may have missed it, RWD or 4WD?

As far as I can tell, the ZW7 Premium Smooth Ride on the NNBS trucks does NOT use Nivomat shocks. That AC Delco replacement @PNW VietVet posted is clearly not Nivomat technology -- not at $55 -- and, from the pics, your shocks are also not Nivomat, but do look like OE to me. Doesn't look like you have many options, as I see that KYB doesn't make a compatible shock if my search was accurate.

You may need to upgrade the rear springs for a better load leveling experience. Others with NNBS suspension experience will chime in.

 

[Erock7625]

Thanks, so despite being a ZW7 they are basically standard shocks. It’s a 1500 XL SLT RWD. Looking at Rockauto it looks like I could replace them with the Rancho RS55262 or the Biltstein 24186834. Not sure the Rancho is better than the AC Delco one as its $46 vs $54, the Biltstein is $74.


BILSTEIN 24186834 {#25871234} B6 4600 Info
Rear; Without Air Leveling Suspension; Without Z55 Autoride Suspension Package

RANCHO RS55262 {Click Info Button for Alternate/OEM Part Numbers} RS5000X Info
Rear; w/ 0" - 3/4" Rear RAISED Height; without Magnetic Ride Control; without Electronic Suspension

Rancho also shows this shock fits which is a better model:
https://www.amazon.com/Rancho-RS7262-RS7000MT-Monotube-Absorber/dp/B07JVBX7M1

 

[Doubeleive]

go to the ac delco website and punch in your vincode and look for the oem replacement and try and find the originals, If you have the nivomat I would stick with them, I don't know of any equal out there, I had changed mine at one time and was pretty disappointed I was even more disappointed that I had already tossed my old shocks and had to fork out about $500 each for new oem ones

 

[Foggy]

With those being just a "standard" shock, anything will be an improvement over
worn out shock...The bilsteins are the bomb, KYB are very good too.
If you aren't needing to "improve" much over stock, then go with those..
The ranchos seem to fit better with off roading and when you need more
travel for specific situations....
The monroe OE Spectrum shocks suck... good for a year at best.

Like I said, a good quality OEM replacement shock will be your best best
and pretty easy on these to replace too !!!

 

[kbuskill]

I would install a set of load helper bags in the rear springs, that way you could air them up when you load the truck down with stuff and not be stuck with a stiff ride when unloaded.

https://www.airliftcompany.com/shop/60769/

Shocks aren't designed to carry weight, unless they are Nivomats, they are designed to control rebound.

A set of old school air shocks would also give you some extra weight carrying capacity.

 

[Erock7625]

Thanks all I ordered the Biltsteins, those air assist bags look interesting and are not that expensive. I’m probably only hauling about 500 pounds of gear in the rear so not sure I need them. Since the vehicle has the factory hitch I assumed it would be equipped to handle the extra weight. If I do decide to tow a RV at some point am I going to have to beef up the suspension even more?

 

[Fless]

If I do decide to tow a RV at some point am I going to have to beef up the suspension even more?

For the suspension you would probably need the bags, and your trailer would use a weight-distribution hitch (WDH).

 

[OR VietVet]

For the suspension you would probably need the bags, and your trailer would use a weight-distribution hitch (WDH).

Love the WDH set up. Especially with sway control, when needed.

 

[Erock7625]

I ordered the Biltsteins to replace the current OEM shocks but I know that will not help with my sag when the back is loaded. Trying not to go the helper bag route, would replacing the coil springs help with carrying the load better and avoid rear sag? My 3 options are AC Delco variable rate, Moog constant rate or CargoMaxx variable rate. Trying not to change the height of the rear when empty.

 

[wsteele]

Thanks all I ordered the Biltsteins, those air assist bags look interesting and are not that expensive. I’m probably only hauling about 500 pounds of gear in the rear so not sure I need them. Since the vehicle has the factory hitch I assumed it would be equipped to handle the extra weight. If I do decide to tow a RV at some point am I going to have to beef up the suspension even more?

You might want to do the math and make sure you are keeping things within design GVW. It sounds like with the rear loaded with all your gear, the tongue weight on your trailer might be putting you well over the line on your total payload.

 

[Erock7625]

Actually no trailer, just maybe around 500 lbs of gear tops on a roof rack, in the back and on a small cargo carrier attached to the trailer hitch. The rear sits about an inch or two lower hauling that and I’d like it to stay a bit more level so I’m not constantly flashed by people thinking I have my brights on

 

[Erock7625]

I guess what I'm most wondering are these Dayton CargoMaxx HD springs worth the $100 more than the AC Delco springs or presuming the rear springs are just worn will the AC Delco springs help handle the load better. This CargoMaxx line seems brand new and was the result of an acquisition they made, they are pretty much zero reviews on them on the internet. The description sounds good carrying 35% more load at stock height but is it worth the extra $100 over the AC Delco's.

 

[wsteele]

Actually no trailer, just maybe around 500 lbs of gear tops on a roof rack, in the back and on a small cargo carrier attached to the trailer hitch. The rear sits about an inch or two lower hauling that and I’d like it to stay a bit more level so I’m not constantly flashed by people thinking I have my brights on

Oh got it, not sure where I got the trailer thing in my head. 500 lbs definitely won't be taking you near max payload, unless you have a soccer team in the car as well.

 

[Erock7625]

ha, yeah think I mentioned I might tow at some point, right now just trying to handle the load without towing. I guess I'll bite the bullet and get the CargoMaxx springs and see how it goes.

 

[swathdiver]

Trying to make sense of what shocks I have ...I have the ZW7 premium suspension that supposedly includes Nivomat self leveling shocks in the rear. ...my other option codes are 6XU and 7XU whatever those mean.

You'll want to put Air Lift Springs, 60769 in your rear coils to keep her from sagging under the additional weight.

You do not have Nivomat shocks, those ended with the GMT-800s.

We have essentially the same vehicle an configuration and my rear shocks are 25871227/540-435 and the springs are 25783733/45H2164. 6XU and 7XU are the codes for your front shocks. My front shocks are 20765171/540-460. My front springs are 25876861/45H0427.

You can look up your front shocks here using those codes and your VIN:

https://parts-catalog.acdelco.com/catalog/catalog_search.php

 

[Erock7625]

I'd rather not go the Air Lift route and just try and stiffen up the coils. If I bought new 45H2164 for the rear would that help over the current worn coils? The other option I was looking at was the Moog 81071 coils, I was going to try the 81069 HD coils but don't want the 2" lift that comes with those.