Rear shocks with ZW7 RPO Code

1ASERMAN

MEMBER
2005 CHEVROLET TAHOE
5.3L
V8
2WD
AUTOMATIC
170,000 MILES

I replaced the original shocks on my SUV 8 or 10 years ago and they did okay. I changed them again last year, but they are not working right, seem to have some play in the full extension. They rattle when going down a dirt road.

I found out that there is an RPO code when purchasing shocks. This vehicle has an RPO code ZW7. I called the local dealership to confirm, and they said yes, you should have premium ride suspension on that vehicle. There should be a wire going to the rear shocks. Well, no there isn't nor has there ever been one. I took the original shocks off and there was never any harness connected to these shocks. I have a VIN number and can provide one but would like to get an opinion of which shocks I should purchase for this truck without easter egging in my selection process. I want to get it right this time and stop jarring my eyeteeth out.

Looking for some assistance where someone may be able to provide some insight with what rear shocks I should get.

7 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

There are three RPO codes that are related to the conventional type shocks on this vehicle. Most commonly you will find the ZW7 or a Z66 code. These are conventional shocks and are interchangeable. Standard aftermarket shocks will fit any type of conventional suspension.

If you had ZW7 along with the Z55 Autoride, then it would be an electric shock.

Explain to me what exactly is happening and what brand of shock you purchased. I believe this vehicle came with an AC Delco part.

Take care,

Joe

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Tuesday, February 15th, 2022 AT 6:26 PM

1ASERMAN

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When the truck is sitting on a level surface, the shock when grabbed by hand rattles where it sits. At this position, I would think it should be under some pressure and not move at all.

Looking back at the receipt if when I purchased these shocks, the front ones say they are for ZW7 and the rears were not, so I was failing out of the gate.

Looking at the codes again, there is no Z55 code listed. I checked again around the rest shocks and there is no wiring harness or connector present, so I know there was never any electrical connection previously in the original shocks but all of the ZW7 shocks I'm seeing is showing to have some connector.

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Wednesday, February 16th, 2022 AT 2:13 AM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

The RPO you have can have with or without. I suspect your vehicle came without them. However, the RPO you provided is correct and based on options, doesn't necessarily have to be electric.

IF you can rattle the shock back and forth, replace them. You are correct when you say there should be tension on them. By chance, where do they rattle from, the mounts or the shock itself? Also, let me know what brand shock you got and the part number. Based on your description, it sounds like the shocks are bad.

Take care,

Joe

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Wednesday, February 16th, 2022 AT 3:43 PM

1ASERMAN

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Joe,

KYB 344384 was the part number, and it did not include the option Premium Smooth Ride Suspension, however, it was listed as a fit for my vehicle. After more research, it appears the one and only shock that will work is the OEM AC Delco model that I avoided because of the price but it is the only one I'm finding with no aftermarket model except for Bilstein model that when priced, is similar to the cost of the OEM so I'll just go that direction. The AC Delco model that I've found and y'all can confirm is the 580354 and matches the required ZW7 and G65 RPO code as listed in the glove box.

I'll have to order the new shocks and get them installed and then file a warranty claim (I have one year) on the old shocks and that'll help offset the cost, provided they see the same I'm seeing and properly compensate me.

John

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Wednesday, February 16th, 2022 AT 4:04 PM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

Yes, that appears to be the correct shock. Let me know if it takes care of the problem.

Take care and let me know if there is anything I can do to help.

Joe