Powerboost Clunk (video link)

[loganlaporte]

Guys, and maybe @Snakebitten you can help.
I am getting a clunk as the engine turns on and off.

I’m spitballing here but guessing it’s coming from the heat exchanger. It happen driving and parked. More pronounced when parked because there is no ride noise. It is causing a noticeable vibration/oscillation in truck when it happens.

Link to video below:

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[thebigdu]

I *think* my truck does this...? Always assumed it was normal for the PB. Lots of strange noises here and there that I never had with non-hybrid vehicles. Is the clicking particularly loud from inside the truck or standing around outside the truck, or only when you're underneath?

 

[Snakebitten]

That's certainly a clunk!

I would just make sure that you can isolate the noise being from the exhaust heat exchanger rather than from inside the plastic transmission pan.

The one difference you could also look for is if it was related to the transmission auxiliary pump, it would happen regardless of the engine coolant temperature because the transmission is ALWAYS going to switch from the gear driven transmission pump to the Electric Auxiliary pump everytime the ICE switches on/off. But I would assume once the truck is at full operating temps the exhaust heat exchanger is no longer necessary for heating the engine coolant so a noisey servo-valve wouldn't change its state of open/close.

Spitballing with you a bit.

 

[loganlaporte]

Its a pretty noticible noise. It does it on both ICE start and shutdown. The only reason I bring all this up is my other PB didnt have this noise.

Its like a valve/ servo triggering. Any other pumps it could be?

 

[thebigdu]

So the video is of the clunk at ICE startup, right? Mine definitely makes this same noise, and now I'm wondering if my EV/ICE transition is harsher than it should be due to an issue.... Watching thread...

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