I installed bilstein 5100's on the front a year ago and they were great, big improvement on the ride. BUT, I just installed bilstein matching shocks on the rear, and they are terrible. There is a loud/ noticeable drop/ bang in the back now over bigger bumps. Over smooth road they're fine, but I'm wondering if its maybe not the shocks and something else since that seems to be strange for a brand like Bilstein, everutjing I read looked good.

The absorber mounts/ pad look fine, no excessive wear, and the leaf springs look ok with no cracks (one was creaking the other day but sprayed it with wlg and its fine).

Any suggestions?

2008 H3 Alpha, 200,000km

 

Exactly!
I swapped out all stock shocks to: "BILSTEIN B8 5100"s.
Front feels fine, with torsion bar lift, nice and smooth.
Back, over bumps it sounds like something is dropping/loose.

It is on my to do list to inspect/debug it someday.
Remove spare tire/holder and check if something else might be loose there, door hinges, amp, maybe fuel tank is loose?

 

check your body bushings.

 

I recently installed Bilstein 4600's and have had no issues. I've heard the 5100's are designed for lifted trucks and ride a bit stiffer, but not sure if this is true.

 

Still the highest rated SUV shock:

 

I found fold-able shovel in back doors that were not secured, removing it definitely reduced the bang noise.
But, will check body mounts!

 

Its almost 99% NOT the body mounts. All higher mileage H3s we have owned or serviced have had the same clunk and each time it was the rear door latch. It is made of relatively thin metal bolted to the body and the door is a wedge that ramps into the body side catch. The body side spreads apart over time and causes the door to be able to move up and down creating the clunk. If you take the body side off and put it in a vice you can "squeeze" it a little tighter which will stop the noise for a year or so.

 

I had a look at the rear door latch. Do you mean the BODY SIDE CATCH should be removed and squeezed, or above it the metal latch (J hook/ U shape, mounted as the higher of the 2 items on the body side)?

I tried squeezing the J-hook part closer in toward the U shape on the top metal latch part, tried separating (with no luck) the bottom piece a little further (pushing it outward), and tried crimping in the door-side lower V-shape ramp piece (for a tighter fit). With the body side piece off (the one with the 2 black rubber sides), I fit it into the trunk-side ramp piece and it was pretty snug.

I'll see if that body-side, upper latch tightening makes any difference. That just goes into the actuator in the trunk, though, right? So would that cause up/ down movement?

I made sure all the Torx bolts were tight as well.

Also tightened all 4 spare tire mount bolts, as well as the lug nuts on the spare tire, and every other bolt inside (jack, wiper motor bolt, etc.).

Let me know your thougths on your comments re: the door latch.

 

While cleaning headliner, found out that headliner at the rear is very loose and might be source of thuds!

Will add some padding at some point inside.
Not sure if this is by design or previous owner did something.

 

Someone suggested putting a rag over that lower "catch" for the rear tailgate door. I did and it made it a little better, so had my shop order me the replacement parts (the body side and door side). WHAT A DIFFERENCE. That did the trick. No more bouncing around. I guess after 12 years and 200k the rubber wore out (even though it looked fine) or the metal separated.

Part Nos. 15285253, 15285254. Cost a total of $40, installed. Not bad...apparently I got the last one in stock in all of Canada for the body side and had to have one shipped up from Michigan for the door side. Getting harder to find these little odds and ends!

Kudos to you atvspeed4 for the heads up...wish I had a vice that strong, but for $40, got me a new sounding door!