Question about ZW7 Smooth Ride (Nivomat) shocks

[CountryBoy19]

My 2005 XL has ZW7 listed on the RPO codes. The shock absorbers are a smaller'ish diameter (maybe 2.25") and blue color.

However, every time I've been to a scrap yard and found a vehicle with ZW7 suspension the shock absorbers are black and larger diameter. Previous to a few weeks ago all the models I found with ZW7 were pre-03 so I assumed it was a change in shock design when the big changes came about with the 03 model year.

However, I recently saw a newer model with ZW7 that still had those large diameter black shocks...

Is it possible my smoothride shocks have been replaced?
How can I tell for sure?

If so, I want to verify the coil springs were replaced also, how can I tell if they've been replaced?

 

[mizzouguy]

The larger diameter shocks are the zw7 shocks. My 04 had it. Replaced with aftermarket belltech shocks when i lowered it, not sure how to identify the springs, but they do have to be changed as well. Might have a tag on them...
If you arent sure, then you would have to replace the springs to match your existing shocks or replace the shocks and springs both to convert back to zw7. The zw7 springs were softer and dont perform well with standard shocks.

 

[BADRIDES]

I have a set of the black Nivomat shocks for sale that came off my 2002 Tahoe.

 

[Massfloefi]

There are at least two versions of those blue shocks. I would know because I made the mistake of ordering them for my Denali after converting to a standard shock and spring setup. The ones I have are listed as a ZW7 replacement. I would assume that they should work with your stock springs. That's if they haven't been changed as well.

Check RockAuto and you will see the blue ones are listed for your setup with ZW7. Unless your truck is riding weird I wouldn't worry to much about it.

 

[CountryBoy19]

There are at least two versions of those blue shocks. I would know because I made the mistake of ordering them for my Denali after converting to a standard shock and spring setup. The ones I have are listed as a ZW7 replacement. I would assume that they should work with your stock springs. That's if they haven't been changed as well.

Check RockAuto and you will see the blue ones are listed for your setup with ZW7. Unless your truck is riding weird I wouldn't worry to much about it.

Unfortunately, after wasting some of BADRIDES' time getting pictures and negotiating on the shocks and springs, there appears to be some truth to this.

I was under the impression that ZW7 Premium smoothride suspension meant Nivomat shocks. I don't believe it does. At Rockauto there are 2 different AC Delco shocks listed, the blue one like I have (ACD#: 540-433) for ZW7 Premium smooth ride chassis package which cost ~$50, and the fat black ones (Nivomats, ACD#: 540-532) for ZW7 Premium smooth ride chassis package, G65 Self-adj manual level control

This would indicate the RPO code for Nivomat shocks is G65, not ZW7.

ZW7 must be some other part of the suspension. Maybe total combined spring weight? Durometer of the rubber bushings in the suspension components? Jounce stops? I don't have a clue.

 

[Tonyrodz]

I have the ZW7 code in my 03, and it had the fat black shocks, no G65 code.

 

[CountryBoy19]

I have the ZW7 code in my 03, and it had the fat black shocks, no G65 code.

The plot thickens... maybe it's model year dependent?

For 2003 the small blue shocks 540-433 are not listed but it lists 2 different nivomats

ACDELCO 540533 {#12477645} GM Original Equipment Info
Rear; 4WD; Self-Adj Manual Level Control(G65), Premium Smooth Ride Chassis package(ZW7)

ACDELCO 540532 {#12477517} GM Original Equipment Info
Rear; RWD; Self-Adj Manual Level Control(G65), Premium Smooth Ride Chassis package(ZW7)

For 2005 there are 2, the first is a non-nivomat and says 4WD and costs only ~$50. The 2nd is a Nivomat but it says it's for RWD

ACDELCO 540433 {#25871225} GM Original Equipment Info
Rear; 4WD; Premium Smooth Ride Chassis package(ZW7)

ACDELCO 540532 {#12477517} GM Original Equipment Info
Rear; RWD; SELF-ADJ MANUAL LEVEL CONTROL(G65), PREMIUM SMOOTH RIDE Chassis Package(ZW7); EXCEPT "OFF ROAD" APPEARANCE package(BPH)

I'm confused for sure at this point... I'm going to look at other model years

ETA, 2001-2003 are the same as listed above (Nivomats are the only option), and 2004-2006 are the same as the 2005 example above (2 different options).

So apparently I wasn't too far off on my initial assessment of being model year dependent. The recent late-model NBS I saw with ZW7 must be a RWD with the G65 code as well (which gets Nivomats).

It appears that I do not have Nivomat shocks, but are they self-adjusting another way? I definitely don't have the air-suspension either. The odd thing is that while I haven't put a heavy trailer on mine and measured sag, with several hundred pounds of gear and kiddos loaded in, mine doesn't sag any noticeable amount.

I'm confused as to exactly what type of shock absorber I have at this point. The replacement cost says I cannot possibly have a complex, self-adjusting shock. Yet I have the ZW7 suspension.

 

[eohat]

My ’01 has both the ZW7 and G65 codes. I did a ZW7-delete a while back so I don’t have the ZW7 springs or Nivomat shocks anymore. I don’t know if you’ve seen this link or not but they have some info on the different suspension options.


https://www.shockwarehouse.com/news/gm-suv-suspension-decoder.cfm

 

[mattbta]

Yeah, my 04 RWD has G65 and ZW7 and has Nivomats for sure.

 

[Massfloefi]

The plot thickens... maybe it's model year dependent?

For 2003 the small blue shocks 540-433 are not listed but it lists 2 different nivomats





For 2005 there are 2, the first is a non-nivomat and says 4WD and costs only ~$50. The 2nd is a Nivomat but it says it's for RWD





I'm confused for sure at this point... I'm going to look at other model years

ETA, 2001-2003 are the same as listed above (Nivomats are the only option), and 2004-2006 are the same as the 2005 example above (2 different options).

So apparently I wasn't too far off on my initial assessment of being model year dependent. The recent late-model NBS I saw with ZW7 must be a RWD with the G65 code as well (which gets Nivomats).

It appears that I do not have Nivomat shocks, but are they self-adjusting another way? I definitely don't have the air-suspension either. The odd thing is that while I haven't put a heavy trailer on mine and measured sag, with several hundred pounds of gear and kiddos loaded in, mine doesn't sag any noticeable amount.

I'm confused as to exactly what type of shock absorber I have at this point. The replacement cost says I cannot possibly have a complex, self-adjusting shock. Yet I have the ZW7 suspension.

I hear you with the confusion. Why do they list the blue ones as a replacement for ZW7? Are they just a cheap alternative to Nivomats that are not self-adjusting but can support the weight and provide similar dampening characteristics in conjunction with the original springs?

I purchased the blue ones and they are still on my truck. I like them better than the Bilsteins that I replaced but they have a similar harshness over pot holes and other road imperfections. I am going to replace them with KYB excel-g's tonight if my truck gets back to me early enough. It's in the shop for a couple things. I know Tonyrodz hates his KYB excels. Is it because his truck is dropped and the shock travel is affected? I am only guessing but it seems that a lot of us with ride issues comes down to the correct shock to spring combo after we convert from Z55 or ZW7 G65.