2020 Startup "Thunk"

Hey guys - noticed a few times recently that while starting the truck, there is a "thunk" or "clunk" that feels like it's coming from under the floor board while the clutch is depressed... honestly feels like the clutch isn't fully pressed in and the trans "catches" while the truck turns over. It only makes the noise once, truck still starts fine, and doesn't jolt forward or anything like that - and the clutch is fully-engaged so I know it isn't or shouldn't be catching anything. It doesn't happen every time the truck is started, no idea what it is. 99k miles, no other issues, truck drives fine otherwise and no lights...

 

Is it anything like what I and a few others have recorded in this thread?
https://www.tacomaworld.com/threads/strange-clunk-on-start-up.794029/

 

Yes it’s exactly that. Thinking more about it, I have only had the issue after shutting the truck off for a short period and getting back into it/starting it. I guess the explanation of the fuel back pressure somewhat makes sense?

 

Yeah it does seem like the most likely answer. Makes sense with it always happening after a short time off at the gas pump.

I have not had it come up for a while now on mine but i moved from az to washington state so I'm not sure if that had something to do with the change in the problem happening. But i also have not driven it as much as i used to. Still never had any problems with anything else, no failed starts ever. But its interesting to know its not automatic or manual related. If i ever get it figured out by the dealer i will for sure post it on that thread. I doubt its a missing tooth on a starter or flywheel but if i ever/when i have to swap out the clutch or throwout bearing i will for-sure take a look. Idk if there is anything they can do for it if it is that fuel issue. Hopefully it doesnt cause any problems in the long run.

 

Yeah, it doesn't seem to me like the starter is missing a tooth or the flywheel is damaged etc - I think we would have more or other symptoms if that was the case. I am still on the original clutch @ 99k miles, and there are no issues there, it honestly still feels new, but I don't beat on it or tow with it. My throwout bearing is a little noisy when its cold idling, but by all accounts that sounds like it's a normality on these trucks with the constant contact TOB. I guess I'll just stop worrying until something tangibly goes wrong!

 

Yeah hopefully it never turns into anything, thats funny my tob was noisy last winter and i bought a new one a clutch and pressure plate just to swap it out while i was down there, only for it to stop making noise after it warmed up. At 53K rn now so ill just sit on those parts until i need to do it. I did some rough ish offroading but yeah no issues on anything else. Hopefully its just a small quirk in a reliable truck. Better than the crap going on with some of these 4th gens

 

Last time a heard a “thunk” noise was when a cat slept on top the radiator fan shroud and died on the way to work in front of the radiator.

 

I'll bet it was quick.

 

Rip pussy cat