4wd vs. 4wd z71

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Fless

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What RPO codes do you have for suspension? If they are ZW7 with G65, that's the Premium Smooth Ride and that has softer rear springs to go with the Nivomat self-leveling rear shocks. If you have those codes, do you know if the rear springs were changed with the Rough Country lift?
 
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ChevyGirl89

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I will have to look at the codes tomorrow, I dont know if the springs were ever changed. I just know the guy before me had the level lift put on and it has the spacers on top of the spring, they looked to be 1in. It does have almost 226k miles too.
 

EddieC

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My '08 Z71 had different shocks. They were by no means harsh so I replaced them with the same when one failed after many years. Modern upgraded oem suspension is not rock hard like in the old days. I hesitated on our C5 vette but, again, the sporty suspension was very complacent.
I can't say what other suspension parts were different on the Z71 but I suspect the rear sway bar was an upgrade.
We also got 18" wheels in the package that look nice but a bit of an oddball tire size. They are not lacking in sidewall so the ride was not regrettable.
 
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ChevyGirl89

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So here are my codes, I did search the rough country level lift that’s on it and there are 3/4in spacers in the rear. Trying to decide if I should leave them when I upgrade to springs to the Moog HD ones.




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Fless

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I would venture a guess that it squats because the Nivomats were removed but the softer springs weren't. Perhaps the spacer was meant to compensate but that's not enough to overcome the soft springs. Bilstein indicates shock replacement for the rear shocks (from Nivomat to conventional) should include changing the springs. Is there a tag with a part number on your springs?

From RockAuto:
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ChevyGirl89

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Yeah when I got it, the man before had the rough country level kit with keys, spacers and shocks put on. The sway bar links were shot and the shocks weren’t the greatest so I bit the bullet and purchased these bilstein shocks. I have always had chevy trucks, this is my first Tahoe so I’m learning on the things that differ from the trucks. We just got back from vacation and done a roungh measurement and my front fenders are around 38 1/8 and the rear was about 36 7/8. But I haven’t had a chance to measure on flat concrete


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Myfirstz71

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The RPO code ZW7 refers to your suspension package. Z71 is obvious, Z55 is air ride. I would second @Fless’s assessment that the shocks were changed out from the nivomat to standard without taking into consideration the softer spring rate of the rear springs. If you change out the springs in the rear to Z71 OEM or the moog, this should resolve the sag.

You might even be able to ditch the spacer since the new spring will not sag nearly as much under the weight of the rear end. Try new springs with out spacer, take measurements, and if you don’t like it, easy enough to add the spacer back in.
 

bobsburban

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The 5100 Bilsteins are good but aren't designed as springs (duh). I'd say call Moog and order their version of the Z71 coil springs, which should be what you have on a 1/2 ton SUV. I can confirm that when I did my Z55 delete on my 2011 Suburban, the springs I got from Moog were about 250 lbs stiffer than the Z55 springs, They were also about 2" longer. That should help. Given what was done to the front end to level the truck, it's little wonder the rear squats with that kind of rake. I fight the same issue on my Suburban when towing as I "leveled" my truck by setting the front springs on the first perch from bottom on my front 5100s. I'm still working with my wesight distribution hitch setup to get things as level as possible with 500-ish pounds of hitch weight and water and an ice chest full of drinks in the back of the Suburban.

Good luck.

Edit: pretty sure springs on 2500 trucks are all leaf springs, springs on 1/2 tons, except the really older ones, are coils. Not sure how that works into your year but if 2500 leaf springs are an option, that could be a good move if they fit. Otherwise, Moog is your friend; call them direct and verify the part number for their stiffest coils. I don't think GM makes/stocks these anymore. I had no luck when I was looking for them.
 
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