Rear coil spring insulator
 

Is there anywhere to get these except for the dealer ? You can find the front but I don't see the rear listed anywhere thanks .

Rear Spring Lower Seat - GM (25993738)
What's wrong with a dealer ? They don't seem to be very expensive.
A Google search of the part number above, shows them as cheap as $3.73.

Thanks right after I posted this I found the answer Lol . when this part failed I tried the dealer and was told they couldn't get the part either thanks anyway

looks like it's been discontinued, that's why they couldn't get it...
if you get lucky hunting online for NOS, either of these #s will work

https://cimg0.ibsrv.net/gimg/www.che...69e2f2f3d1.jpg

If the insulator was missing would this cause the spring to rattle like crazy ? Looking at the picture I found there is a bump stop mounted on top of spring could this part make the rattle when going over bumpy roads.

Yes, and the bushings on the shocks and swing arm. Spring may be broken. If you are sure it's coming from the rear.

Check the springs real close. They've been known to break down on the bottom.( Hard to see the break.)
The upper part of the spring seat is called a jounce. A lot more $. Something like $35 a piece last time I looked.
Here's a pic that shows the jounce on my SS when it was pretty new and still clean. The tan colored foam disc is factory. Not sure if you get one of those when you buy a new upper jounce.
https://cimg4.ibsrv.net/gimg/www.che...7d959d531e.jpg

Looks like we need the jounce bumper part we changed rear shocks and the foam part was just hanging around the coil spring gm # 25993737 this my son's car I drove it today it's definitely the rear rattle's like crazy been this way for a while after some more searching on here I'm thinking he may have a broken spring if we put the rear on the car on my ramps could we maybe find what the problem is ? As thanks for the info.

Might take a shot at RockAuto, they are doing a wholesaler closeout and we have a discount code. https://www.chevyhhr.net/forums/supp...-2022-a-61707/

If you take both shock off the swing arm will hang to inspect the bushings and the springs.