Start Up Sequence? (Noise Investigation)

I hear the same noise on startup, usually on a cold start or when the engine hasn’t warmed up. Less than 200 miles on mine though, I was paranoid as can be but sounds pretty common

 

I’ve heard this as well in my truck maybe 3 times, only at 700 miles currently. All were cold starts.

 

I hear the same noise on mine. Googled around awhile ago and consensus was AC compressor, when your AC is on auto and it's hot outside.

 

Sorry but Google is wrong. I took delivery of my truck on 12/15/21 and didn't use the A/C at all for months. The noise is not tied to A/C usage. At least, not in my case.

 

Did you use the defroster at all during those months?

 

I don't recall. We only got 1 day of snow here over the winter so I doubt it. It's so dry here (desert) that I don't think my windows have ever fogged. Even in winter our humidity will be below 15%.

 

I was just asking because the defroster uses the AC system to draw the moisture out of your cab and clear up the windows quicker.

 

Ahh. Gotcha. Yeah, that makes sense.

However, I don't think the defroster is ever "On" at startup, is it? So the startup noise wouldn't be a result of the A/C from the defroster.

I.E. Even if you left it on when you shut the car off, unlike other climate settings, you have to reengage it the next time you start the truck, or am I wrong about that?

 

Mine makes the same noise at start up. almost 2000 miles. I never really noticed it until about 600 miles ago.

 

I'm honestly not sure if the 3rd gen does stay in defrost but I know my 2021 Tundra does along with my wife's Highlander. I just assumed it was a normal Toyota thing.

 

You might be right. It's been 10 years since I lived in a place with any type of serious winters. lol.

 

I'm hearing a "ting" sound after I put the truck in D and the drive after 5-10 seconds. It's only then I hear it. Anyone know what that is?

 

I have a 17 sr5 with 30,000 and I hear the same dink noise for a second then not again till I turn it off and back on again. It has to be in motion and only happens in the first 100 feet. Thought maybe something in the tranny an internal part expanding or seating due to thermal expansion but that's just my guess.

 

I hear the same noise occasionally. It just so happened that i had my hand on the gearshift when i cranked it one day, and I could feel the noise in the gearshift.
I am no mechanic, and I have no idea what that means. I searched for this thread, but could not find it. Glad it came back up.

Anybody else feel it in their gearshift when they hit start button?

 

I was having the exact same issues as discussed in this thread then I started paying attention to my start up sequence.

I only noticed the noise during cold starts or if the truck had been sitting for long periods since I bought it new (it now has 2000 miles). I always just ‘clicked’, hit it fast, the start button. I figured I would try holding the start button down until the truck fully started and bam no noise ever. I say ever, you might get a small hint of one maybe 1 of 10 times but that’s it. You have to know what you are listening for to even hear it then

So a simple solution, at least for me, hold down your start button until the truck fully starts and no noise.

 

I’ve heard it on my new truck as well a few times. After studying the noise I believe the clunk at startup is definitely related to the AC compressor engaging.

 

I have the same issue with mine and I was going to ask my dealer when I go in to pick up my predator steps. Im here for answers

 

I don't think dealers know. If you pick through this thread, dealers have blamed this noise on everything from AC compressors to the Air Injection Pumps. I'm not 100% sold that it's any of these. I hear the noise when there's no reason for the AC compressor to engage at all (Neither the AC nor the heater/defroster are on).

Unless Toyota Engineering release a TSB on it or we start seeing component failures en masse, I don't think anyone will know for sure.

 

I got my 1794 Tundra in back in May. I heard this clunk sound (1 clunk or 2 clunks) for once every 5 starts or so. Now it's about once every 2-3 starts. I am embarrassed starting this truck when I am in public. What a shame to be the owner of this 70k new truck.

 

It is a bit embarrassing at times LOL. I had someone ask me if it was a diesel after hearing it start up recently.

 

I hear it on mine ocassionally, hadn't associated it with whether it's cold or hot though. Mine definitely comes from behind the driver though, most likely the aft portion of the tranny.

 

I am thinking this has something to do with automatic parking brake, but I am no mechanic.

 

The noise was happening to me since I got the truck, but after going in for the EPB recall a few days ago I haven't heard it since. I dont know if coincidence or not.


False alarm it came back..

 

Did anything ever come of this?

 

I have to admit, when I read this a couple months back I thought this sounded crazy, only because I couldn't figure out how or why you would have had your hand on the shifter while it cranked since I typically use the same hand to hit Start as I do to shift gears. Anyway... I have since noticed that the shift lock mechanism makes a clunk type noise when I step on the brake pedal while in Park. The noise sounds quiet similar to the clunk I was getting on startup, quieter but definitely related. I started messing around with my starting routine and started purposely holding onto the shift lever during the start sequence and noticed I definitely could feel the suspect clunk in the shifter every time it did it like JBASS2 mentions. Next I started to release the brake pedal immediately after hitting the Start button rather than maintaining brake pressure through the whole crank sequence like I typically would. This new routine, even though it is strange and unnatural feeling still, has completely eliminated the weird startup clunk I've had since new. I have not had it happen a single time over the past several weeks and many starts.

Take this however you'd like, try it out maybe... Makes me believe there is something going on with the shift lock mechanism or shift mechanism that is feeding back through the shift cable into the shifter. Maybe I'm also crazy, or maybe this will lead to the cause of this potential issue.

 

I occasionally hear a clunk upon start up and coming from a Raptor I got used to all the noises lmao, I initially thought about the turbo waste gates possibly making the noise, I just figure let things be as I’m still getting used to the new truck

 

I remembered your post and held the shifter (a little awkward BTW) during startup. I 100% felt the same feedback in the shifter handle when the clunk happens.

I don't get the same feedback or noise when stepping on the brake while in park like you mentioned. I only feel it during the random startup clunk.

I've tried letting off the brake immediately after hitting the start button, but I still get the occasional (i.e. random) clunk. Maybe I'm not letting off it it quick enough. Either way, I still find it really odd and I'll continue to mention it to my dealer whenever I take my truck in for service. At least they'll continue to document it in the notes in case something fails or a TSB is released about it.

 

Could it be the ABS Self-Check that the 2.5 Gen have?

 

I too have noticed this clunk type noise on some random start ups days after delivery (April 2022). My 5k service is coming up soon and I will definitely notify the dealer about it for documentation sake. I will keep you all updated on what my dealer has to say about it...

 

I have this noise ... not worried about it. no mechanical issues when driving