Z71 on ZW7??

[gmartin1215]

On my 2009 Tahoe 4wd LT, I have the ZW7 RPO code for the Premium Smooth Ride.

Looking underneath, the tags for the front and rear coils were still attached and I was able to get the part numbers.

For the front, both coils have GM #25876851. For the rear, both coils have GM #25978750.

I read recently that GM #25978750 is the same rear spring used in Z71. Huh?!?!

I am not sure if the front coils, GM #25876851, are Z71, too. Can anyone say??

Why would there be Z71 coils for a ZW7?? Is that something GM has typically done in the past?

I assumed I have the Nivomat shocks in the rear since I have ZW7 in the RPO code. But, now I am not entirely sure. I could not find a visible part number, but these shocks do seem to have a large diameter.

My VIN is 1GNFK23059R234842, If there is someone here that has the ability to look up the actual part numbers for my Tahoe, and if it was installed with Nivomats or not.

 

[swathdiver]

On my 2009 Tahoe 4wd LT, I have the ZW7 RPO code for the Premium Smooth Ride.

Looking underneath, the tags for the front and rear coils were still attached and I was able to get the part numbers.

For the front, both coils have GM #25876851. For the rear, both coils have GM #25978750.

I read recently that GM #25978750 is the same rear spring used in Z71. Huh?!?!

I am not sure if the front coils, GM #25876851, are Z71, too. Can anyone say??

Why would there be Z71 coils for a ZW7?? Is that something GM has typically done in the past?

I assumed I have the Nivomat shocks in the rear since I have ZW7 in the RPO code. But, now I am not entirely sure. I could not find a visible part number, but these shocks do seem to have a large diameter.

My VIN is 1GNFK23059R234842, If there is someone here that has the ability to look up the actual part numbers for my Tahoe, and if it was installed with Nivomats or not.

Nivomats are not used on GMT900s. Do you have a Z71?

ZW7 and Z71 are similar suspensions that differ in their use of shocks, they share the same springs.

 

[gmartin1215]

I do not have a Z71. It's not in my RPO codes.

Nivomats are not used on GMT900s. Do you have a Z71?

ZW7 and Z71 are similar suspensions that differ in their use of shocks, they share the same springs.

I do not have a Z71. It's not in my RPO codes.

 

[Dustin Jackson]

@gmartin1215 When I search those part numbers in the description is says "4WD w/o magneride. Coil Spring . W/4WD w/o auto lvlg cntrl" which would indicate that they probably didn't come on that Tahoe from the factory I think?

Take a look at your shocks, the autoride shocks have lines that connect to the shocks to control them, you should be able to see pretty easily if there are lines that go to them.

It might be safe to say that if the springs have been replaced then the shocks have probably been replaced as well. The previous owner probably converted it to a standard suspension.

 

[gmartin1215]

@gmartin1215 When I search those part numbers in the description is says "4WD w/o magneride. Coil Spring . W/4WD w/o auto lvlg cntrl" which would indicate that they probably didn't come on that Tahoe from the factory I think?

Take a look at your shocks, the autoride shocks have lines that connect to the shocks to control them, you should be able to see pretty easily if there are lines that go to them.

It might be safe to say that if the springs have been replaced then the shocks have probably been replaced as well. The previous owner probably converted it to a standard suspension.

Thanks. I know for sure I do not have the autoride - no lines going to the shocks.

@swathdiver mentioned the Z71 and Zw7 for my year Tahoe share the same springs


I called the dealership and got the part numbers for my shocks - 20765171 for the front, and 25871225 for the rear. I asked the dude if the rears are auto-leveling and he said all he saw was premium gas charged for those.

While I had him, I asked what is the difference between the Z71 and Zw7 for the 09 for the springs and shocks. He said the front shocks are the same number, but the rear is 25871229. I tried to ask him about the springs, but he could not find out unless I had the last 8 VIN numbers from someone who has a Z71.

Can someone with a 2007-2014 Z71 Tahoe say what their GM part numbers are for your springs?

I purchased Moog 81244 and 81609 - -thinking of upgrading my suspension to that of a z71 - but if the Zw7 and the Z71 share the same springs, then I likely won't need these Moogs.

 

[Dustin Jackson]

@gmartin1215 When I got my tahoe it had lowering springs on it and now I have Moog 81069 so I have never has my hands on a set of factory z71 springs I am sorry. You could always compare them with your eye, at this age it might be worth just replacing them in case they have started to sag.

 

[gmartin1215]

I finally got a good answer from a GM parts person.

The Z-71 Tahoe for at least 2009 had the following springs and shocks GM part numbers:
Front -
25980102 (shock)
25876851 (coil)

Rear -
25871229 (shock)
25978750 (coil)

The ZW7 Tahoe for my 2009 Tahoe has:
Front -
20765171 (shock)
25876851 (coil)

Rear -
25871225 (shock)
25978750 (coil)

So, same coils but different shocks.
My ZW7 did not have autoride or auto-leveling shocks.


Sorry, if this is already known. I didn't know it.

 

[Fless]

I finally got a good answer from a GM parts person.

The Z-71 Tahoe for at least 2009 had the following springs and shocks GM part numbers:
Front -
25980102 (shock)
25876851 (coil)

Rear -
25871229 (shock)
25978750 (coil)

The ZW7 Tahoe for my 2009 Tahoe has:
Front -
20765171 (shock)
25876851 (coil)

Rear -
25871225 (shock)
25978750 (coil)

So, same coils but different shocks.
My ZW7 did not have autoride or auto-leveling shocks.


Sorry, if this is already known. I didn't know it.

That's good info; thanks for sharing your research!

 

[swathdiver]

I do not have a Z71. It's not in my RPO codes.

I do not have a Z71. It's not in my RPO codes.

Ok, then what you have is the basic suspension, Z71s have Rancho shocks.

Your RPO sheet specifies which springs and shocks you have.

On the old GMT800s, they could have been equipped with Nivomats, and if so, would have had G65 in their RPO sheet along with ZW7.

On my truck the spring codes are YD5 and YD6 and the shock codes are 6RS and 7RS. Yours will likely be different, I provided this to give an example of what to look for. Of course, the best way is crawl under and look for the numbers which I was fortunate to still be able to do.

Plug in your VIN here and have a look:

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

 

[gmartin1215]

Ok, then what you have is the basic suspension, Z71s have Rancho shocks.

Your RPO sheet specifies which springs and shocks you have.

On the old GMT800s, they could have been equipped with Nivomats, and if so, would have had G65 in their RPO sheet along with ZW7.

On my truck the spring codes are YD5 and YD6 and the shock codes are 6RS and 7RS. Yours will likely be different, I provided this to give an example of what to look for. Of course, the best way is crawl under and look for the numbers which I was fortunate to still be able to do.

Plug in your VIN here and have a look:

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

Thanks!
That site is helpful; thanks, for the link!
Mine has YD5 and YD6 for the springs, too,
And 6PB and 7PB for the shocks