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.

 

[BADRIDES]

My 2002 Tahoe has the ZW7 code and it had the fat black shocks with the G65 code.

 

[CountryBoy19]

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'm not really sure.

By my logic, if an 04-06 4WD ZW7 vehicle originally came with Nivomats and AC Delco offers a cheaper replacement (the blue ones) wouldn't there still be a Nivomat option offered by AC Delco?
Furthermore, if they offered a cheaper replacement for the 4WDs, wouldn't they also offer a cheaper replacement for the RWDs?

As it is, according to Rockauto, there is no AC Delco Nivomat offered for 04-06 4WDs, and there is no cheaper blue one offered for 04-06 RWDs.

For 03 & earlier models there is no cheap blue option, both 4WD and RWD have the Nivomat as the replacement, but those Nivomats have different part numbers. This is because the RWDs had a different rear axle than the 4WDs.

It's safe to say that the RWDs are not just treated as the same vehicle w/o a T-case and front drive axle. They call for different brakes and everything so it's safe to say there may be other differences between the two, like suspension differences.

We can also reasonably expect that RWD vehicles are going to stay on the street but 4WDs can be expected to go off-road occasionally.

Maybe the Nivomats just weren't working out in off-road performance?

Understanding all those things, my logic tells me that when they moved from the 03 models to the 04 models, which is when they made a lot of big changes to these, they changed something with the suspension options packages for the 4WDs. The ZW7 no longer meant Nivomat shocks.

 

[CountryBoy19]

The plot has yet again thickened... It occurred to me that I have only been looking at Yukon XL models, because that is what I have. Out of curiosity I plugged in a 2004 Yukon.

While the 2004 Yukon XL model has Nivomats for RWD vehicles and the blue shocks for the 4WD, the 2004 Yukon has only Nivomats for both 4WD & RWD.

It appears that maybe for some reason Nivomats were not included with the ZW7 pkg on long wheel-base 4WDs after 2003. Once again, maybe because they were being subjected to more harsh use/abuse and being damaged? I don't know the reason... dang I would love to get ahold of a GM engineer...

 

[CountryBoy19]

Oops, double-tap

 

[Massfloefi]

The plot has yet again thickened... It occurred to me that I have only been looking at Yukon XL models, because that is what I have. Out of curiosity I plugged in a 2004 Yukon.

While the 2004 Yukon XL model has Nivomats for RWD vehicles and the blue shocks for the 4WD, the 2004 Yukon has only Nivomats for both 4WD & RWD.

It appears that maybe for some reason Nivomats were not included with the ZW7 pkg on long wheel-base 4WDs after 2003. Once again, maybe because they were being subjected to more harsh use/abuse and being damaged? I don't know the reason... dang I would love to get ahold of a GM engineer...

Funny thing is that I know someone with a 2005 Suburban 5.3 4x4 and they do have nivomat shocks.

 

[CountryBoy19]

Funny thing is that I know someone with a 2005 Suburban 5.3 4x4 and they do have nivomat shocks.

I would be interested to know if they also have RPO code G65 ...

 

[CountryBoy19]

I would be interested to know if they also have RPO code G65 ...

Stopped by the salvage yard today; 2 of the 3 Tahoe/Yukon models had Nivomats (no Suburbans or Yukon XLs there). Both RPO stickers for those had ZW7 & G65...

 

[BADRIDES]

See post 11

 

[BADRIDES]

I have priced you everything you need. Dont see why you keep shopping around.

 

[CountryBoy19]

I have priced you everything you need. Dont see why you keep shopping around.

At this point I don't believe the Nivomats are even supposed to be on my XL. I started the thread because I thought maybe somebody had switched out my suspension when it was supposed to be Nivomats; I was looking to return it to the stock setup. But until I get more answers on how ZW7 and G65 are related and why GM seemingly made the change on the long models, I don't have any desire to change my suspension.

I posted the recent salvage-yard RPO info because I believe (at least post-2003) in order to have the Nivomats you must have RPO G65 in addition to ZW7. The fact that both vehicles with ZW7 & Nivomat shocks also had G65 supports my theory.

If anybody knows of any long wheel-base (Suburban, Yukon XL, Esky ESV) with Nivomats post-2003, is there any chance you could check the RPO sheet and see what it says?