Shock & Strut information NEEDED!!! HELP

[lamerem]

Alright new to the group, but here it goes. A couple of suspension questions.

I have a 2011 Tahoe LT 4WD! Roughly 75,000 miles on it and runs great, a little bouncy and have a thump noise when the rear end shocks get extended to far. My diagnoses shocks are worn and warrant replacement. Here is the catch, on the glove box decal it calls out a ZW7 code which I am lead to believe means premium smooth ride (w/Nivomat shocks). WHen I say lead to believe, I mean through online research.

I called two dealers and gave the VIN and both said, no Nivomat shocks and gave me these replacement part #'s:

Front Strut-ACDELCO 20955487
Rear Shock-ACDELCO 22755311

So question is can the code in the glove box be wrong? It clearly has the ZW7 code. Everyone says that the Nivomat shocks are black and huge. The shocks under the truck are blue ACDELCO and don't look any larger than normal shocks.

Second question is about shock and strut manufacturers!

I have been looking at:

Gabriel Max Control
Bilstein 4600 & 5100
Rancho (no series yet, someone just told me about rancho today)
KYB

Now, I know bilstein are good, maybe better than the rest. But seriously what are your thoughts on the Gabriel and the rest? Gabriel comes with a Lifetime no questions asked? The Max Control are nicely priced too! Although Max Control doesn't offer a strut, so the struts would be Gabriel Ultra! In other words I need help! I am not happy with the unresponsive boat traveling down the road, nor the body roll.

Okay, last question.

Thinking about Energy suspensions sway bar links and bushings. What do you think?

 

[Clean07Burb]

ZW7 is the premium smooth ride option, which means you're truck was originally equipped with the Nivomat rear shocks. They may have been replaced at some point with standard shocks. Some say the rear springs on the ZW7 trucks were softer since the shock incorporated some kind of automatic (non-air) load leveling feature, but I'm not certain on the softer spring/non-softer spring deal.

 

[lamerem]

It's weird to me how the dealer seams to be pricing out the normal shock according to my vin number though. I would think they would see it was Premium Smooth Ride, right? Some folks have said if the truck was equipped with Nivomat from the factory and then replaced with regular then it would sag in the rear from the softer springs. However, mine doesn't have any sag. This is so frustrating. I may try to call Chevrolet tech support this afternoon to see if I can pick their brain.

 

[Clean07Burb]

Yes, the dealer should see that your truck is a ZW7 truck just by entering in your VIN number. Maybe try taking your truck there and showing them the ZW7 RPO code in the glove box and see what they say. Ask them why its not matching what they're listing for it.

 

[lamerem]

On the phone with Chevrolet right now and the rep says the truck was built with Premium Smooth Ride suspension. Yet the dealer looks up the VIN and prices me out normal shocks for replacements. Ugh, the shocks on it now are blue ACDELCO and look 4 years old.

So here is a great question, Nivomats are about $200 a pair on Amazon. Do I go back to stock? Move forward with bilsteins or the like? Then the question remains which springs are under there? Ugh, I guess i could replace the springs with Bilstein springs, but I am a bit intimidated by how to replace those. Front strut springs do not worry me, but those backs look like a PITA.

---------- Post added at 01:43 PM ---------- Previous post was at 01:29 PM ----------

Ok, GM gave me these part numbers for the rear shock and coil:

22755311 shock
25978750 spring

again, while the acknowledge the truck is ZW7, I searched that shock number and at $55.93 shipped I have a hard time believing this is a Nivomat!

http://www.amazon.com/ACDelco-540-631-Original-Equipment-Monotube/dp/B0055A473Q

This is just disheartening!

 

[lamerem]

Not quite sure what happened to my last to replies. But I'll recap!

---------- Post added at 06:49 PM ---------- Previous post was at 06:35 PM ----------

Spoke with GM today and confirmed the truck has the ZW7 option and that it was originally built with the Nivomat Premium Smooth Ride suspension. HOWEVER, the part number he gave me was to a standard ACDELCO shock retailing for $59 shipped on Amazon. Something tells me this isn't a Nivomat. So completely confused I called Bilstein directly for advice.

The guy at Bilstein said the Nivomat would be 3" or more in diameter and appear huge compared to the "normal" shock absorber size. Mine are not huge and are the normal blue ACDELCO shocks. However without the "sag" normal shocks would bring on the ZW7 setup he thinks the springs may have been changed in the past. However he said it was hard to believe anyone has messed with the suspension on a 4 year old truck with only 74,000 miles on it. The only thing we could gather was that even though the RPO says ZW7 it may be standard?

Anyway, he recommended the 5100 series front struts and rear shocks:

Front 24-186940 w/adjustable ride height (ability to level the front without a kit)
Rear 24-187237

He also recommends to replace the coil springs in the rear. Now he said he didn't have a spring for my application. However, he said that the previous generation of Tahoe used part #199021. He was fairly certain that this same spring would cross over to my 2011 Tahoe LT 4WD but his computer wouldn't confirm it because it hasn't been tried by Bilstein.

Can anyone confirm his assumption that the 199021 Bilstein springs fit the 2011 Tahoe's?

He also said he likes both the 4600 and 5100. Said the 5100 would be more ideal if I planned on leveling the truck in the future. Then said that the front 5100 strut has milled areas on the strut to change the spring location. Essentially adjusting ride height and leveling without the need of the aftermarket kit.

Anyone level there Tahoe? Does it look stupid? Do I gain anything by leveling?

I'd like to hear from folks who use the 4600 and 5100 series Bilsteins.

UGH, finally at the end here. Sorry this is so long. Like I said I replied earlier today and those messages are now gone, so just recapping.

 

[lamerem]

Update

Just called another dealer (one I actually like to do business with) and he said according to the VIN the truck has a conventional shock absorber in the rear, not Nivomat. So do I assume the springs are normal? I called Autozone and the sell the Bilstein 5100 shock 24-187237 and he said the only model excluded from the compatability list is the Z55 air Ride code. Does that mean the Bilstein 5100 is compatible with both the regular spring and the softer spring for the Nivomat's? Really scratching my head here...

 

[TheAutumnWind]

I have 5100's on my other vehicle.

They are compatible with your rear setup. AFAIK the only reason that they say otherwise is that obviously you would no longer have air ride if you installed a standard shock ( but they are covering their ass).

You don't need the new springs if you are happy with the ride height.

You don't need to spend more (they arent much more though) on the 5100s if you want to keep this thing stock height. If you plant to ever lift/level it then you absolutely should get the 5100's

I have an NBS that was equipped with air ride, now on standard shocks with no other modifications (stock rear springs) and the ride is great.

 

[lamerem]

I don't have the air ride, that would be the Z55 RPO code. I actually (according to the RPO sticker in the glove box) have the ZW7 RPO code meaning Premium Smooth Ride Suspension. What this is, (or was supposed to be) is a Nivomat Self Leveling shock (it levels itself mechanically without air or electricity). When they mount the Nivomat shock they use a lighter/softer coil spring since this specific shock does the majority of the work for the coil spring.

All being said Bilstein said the spring will need replacement, or the shock will prematurely wear and cause sagging.

Now I called a completely different dealer today to see if I could get a pair of normal (non ZW7) springs and the guy was like "you already have them, according to your vin it is NOT a Nivomat setup. So, I shall assume I have a normal suspension regardless of the RPO code.

---------- Post added at 04:03 PM ---------- Previous post was at 04:00 PM ----------

As far as Bilstein series 4600 or 5100, I am going with the 5100. I planned on leveling the front end with an aftermarket kit. However with the 5100 front strut 24-186940 I can use the different coil seat slots to level it without the extra expense. I just hope the 5100 isn't a harsh ride. I'm not looking for a ball busting suspension. Bilstein however assured me that is would provide a great ride with a controlled feel.

 

[lamerem]

I am going back and forth. I have ready some threads where guys say the 5100 is too stiff, and others say the 4600's are. May not lower after all whats best for bilstein series 5100 or 4600?