I've been stubbornly putting off this post for a while thinking that I would figure it out but alas I'm giving in to brighter minds.

Background: 2018 TRD ORP, 6k miles, recently installed the FJ TRD kit in addition with 1" front spacer and 1.5" T13 coils in the back with the OME 10mm yellow spacer on the drivers side to account for lean.

Symptoms: Everything rides great except under a small subset of conditions. When the vehicle is loaded with weight (ex. 4 people in the car) the rear driver side will make this knock type noise when going over multiple small deviations in the road. Think cobblestone or washboard type travel. It really only happens on that type of road however, not big pot holes or gradual dips, etc. It also seems more prevalent when going up an incline.

Noise: It's not tinny or high pitch but also not super deep sounding. Imagine if you wrapped a crescent wrench with one layer of a shop rag and hit the frame of the vehicle. The noise usually comes in pairs like a quick knock or something hitting back and forth. From the driver perspective it "sounds" like the noise is coming from underneath the driver side back seat on the left which matches up where the wheel well/shock/gas tank is.

I thought maybe the coils weren't seated in the upper recess properly, due to the 10mm spacer, and the coil may have been contacting the frame but I had a shop pull both coils out and reinstall them to no difference.

My next thought is something with the sway bar and or end links...maybe torque'd improperly? I'm at a loss anymore. Daily driving with just myself and/or wife in the front seat is great and I never hear the noise but once there is additional weight in the back I start to hear it. I'll try and capture an audio clip of the noise.

Thanks in advance for any input!

My coils (sway-a-way 1.5) pop all the time under medium flex. It is a pretty distinct sound, it has some vibrato associated with it. I am pretty sure they are shifting a minute amount under normal driving then re-seat when I transition through a rut/gutter/curb. For whatever reason I think mine has to do with the diameter of the spring steel not being the same as the stock, either bigger or smaller or the final twists not being exact, who knows. I didn't check when I had them both out. I didn't have any clink/clunk issues prior to aftermarket springs.

I had that happen after a lift too, double check all the bolts that were loosened. One of mine in the rear wasn't torqued right and would pop until we located it

This is what I'm leaning towards at the moment

Check the rear shock reservoirs. There’s been an issue with previous Pro shock reservoirs hitting the bottom of the body cause they’re mounted to high and have to be adjusted a little lower. There’s a few threads on it.

That's a good point as mine basically look like they're touching the frame when parked. I would think I would be able to see some sort of visual clue from it hitting though if that were the case and I don't remember seeing anything. I'll have to take a look though.

Update to the above post- this is my driver side reservoir.


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I've got about 3K miles on my FJ kit with T13 coils and 10mm packer on driver side and have the absolute exact thing going on with mine. Interested to see the solution.

I’m pretty sure that’s your problem. Very consistent with others who have had the trd pro bilstein reservoir touching the inner wheel well. Additional loading would make it happen more frequently, as you have noted.

The solution is to grind out that crescent cut in the inside fender a bit more, or relocate the reservoir slightly. It is my understanding that the stock reservoir bracket engages with a lip that does not allow the reservoir to be nudged up or down...

There are threads about it though! I think it’s will be a simple fix for you.

If I were having that issue, I’d remove the reservoir and get a die grinder in there and make some room. You might be surprised how much the rear shocks move around during normal driving.

Good luck!

I had the same exact problem with my 2017 pro. Basically I *****ed enough about it they gave me the extended warranty for free.

They also issued a service bulletin (T-SB-0006-18) for it this past January. They replaced the full shock/reservoir and installed the correct bracket they were supposed to put on at the port.














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