I recently posted about my 97 Blazer LT and it's fuel pump problems , and thankfully that was resolved. The new annoyance I am having is that a month ago, I replaced all 4 shocks with brand new Monroe Gasmatics. I knew from the outset that these were not the top of the line options I could choose for the Blazer, but at the very least I assumed they would soften the ride and prevent the car from making thudding noises every time i hit a dip or bump in the road. It really hasn't made a difference in smoothing out the ride at all and it is driving me nuts. Apart from the posibility that these shocks just weren't good to begin with, what other components would still create all the road noise regardless of new shock replacement? In the past, whenever I had replaced my shocks or struts, that usually did the trick and softened/smoothened the ride right out. That was even with the cheapest shock/struts I could find. It seems to have made zero difference with this car. I have additionally replaced the entire steering linkage and sway bar bushings/links in this car except upper/lower ball joints (which are still good), control arm bushings, and the leaf springs which aren't really sagging or anything. What do you guys think?

 

I had a thunk in my old '00 Bravada that I thought was the ball joints, but inspection of the ball joints showed them to still be tight. Turned out to be the hood hinges. GM has a TSB (technical service bulletin) out on this and also sells belleville washers to tighten up the joints. As a trouble shooting step, you can put a rag up on the top of the firewall to put some pressure on the hinge and see if the thunk goes away.

Additionally, after replacing the shocks on that same truck, I ended up getting a very similar noise. Turned out that the Monroe Reflex shocks I installed up front were a bit more narrow at the upper mount than the stock shocks. Some additional tightening of the mounting bolt fixed that, but the problem wasn't readily apparent.

You didn't mention what drivetrain configuration your truck has (2wd/4wd), but another possibility if 4wd is the torsion bar mounting bushing.

 

Is the thud from the front end? Might be a bump stop that has broken and fallen off. If one is missing even if the shocks were changed the suspension will still bottom out and cause the suspension to hit the frame.

This post shows where it is located if needed.
https://blazerforum.com/forum/steeri...mp-stop-37209/