Thumping in rear over 70mph?

Has anyone experienced softer thump noises going upwards of 70 to 80mph on FLAT highway roads? It almost sounds as if something is shifting around, but I can’t pinpoint where it is coming from. It’s an '18 sport with 97K miles and clean. Does not happen at slower speeds, over bumps, when turning, etc.

I have tried:
-making sure the seat belt isn’t hitting plastic
-making sure nothing is shifting behind or underneath seats
-making sure the seats/backs are locked in place
-checking the shocks, leafs, etc. it also doesn’t do this at low speeds or over bumps so I ruled that out
-checking for loose bolts, nuts, screws, underneath
-took out a trailer hitch that had some clearance between the walls in case it was that rattling
-closed the tailgate HARD!
-made sure nothing is in the bed
-among other dumb things

Now I’m wondering as I type this if it’s maybe the tonneau cover. It just started to get really cold here and maybe it needs to be tightened? (Thinking out loud here)

I personally don’t think it’s anything serious as it only does it at faster speeds and is not constant, but this is driving me nuts. I don’t feel like heading to the shop and having them look at me as if I’m nuts so I thought I’d try here first. If anyone else has experienced this let me know!

 

Check the weather stripping on the roof where a roof rack would go.

 

all in check! thanks for the recommendation

 

Is it a sport special feature?

Make sure the Spare tire is snug. Check that the chain is not long enough to catch air and hit the spare's rim?

 

I had a screw driver rolling around in my glovebox that annoyed me for a little while until I found it. It was muffled enough that it sounded like it came from outside the cab.

Check the spare tire if you have maybe it needs to be tightened up? I think there is a heat shield around the spare as well, check that for sturdiness? Maybe push around on the gas tank skid and gas tank itself? Are the plastic locking push pins in the top of the rear wheel wells? I’m sure you’ve looked around lol

 

Check the spare tire ?

 

Thanks everyone. I haven’t checked the spare or even thought about that. I’ll try that out. Much appreciated.

 

Slow down. It’ll go away..

 

I've been turning up the music. Same thing I guess lol.

 

If you go faster than 80 mph and then slow back down, does it occur again as you pass through through the 80-70 mph band?

 

Ya it’s pretty random. No cadence at all. I just know it doesn’t happen under 70.

 

Betting as you mentioned tonneau cover.

 

Just tightened everything up, still does it. Now I’m moving on to the spare and checking those heat shields!

 

The actual term escapes me, but cabin vents behind the back seats?

 

Not sure but my 2001 LX470 (land cruiser) makes zero noise at any speed, 235k miles. I swear these third gen Tacomas are plagued and I won't ever agree otherwise. Toyota themselves have admitted their older vehicles were better built.

I have faith in the 4th gen Tacoma for some reason though.

 

interesting thought. Doesn't hurt to check lol

 

The Tonneau cover on mine starts to flap even though it is locked down tight.

 

Tsk tsk, you have a ghost tapping the tonneau cover in the back, trying to tell you to slow down...

Ghost was like "Ahhh.. that's too fast!" [tapping madly on the cover] while holding onto the truck.

Which is why you can't find the problem around the truck.


/shrug

 

I mean, my first thought was that it definitely sounded like someone was trapped in the bed and trying to get out… haha

 

Thats where the Elf on the Shelf is hiding.Happy Holidays