Small motor/whirring noise at stops when engine is off - possible transmission issue?

[LC in the LOU]

2025 LC, about 9K miles. Starting around 8K I began noticing a new noise when I'm stopped in D and the gas engine has shut off. It sounds like a small electric motor running.

• Only happens when stopped with the ICE off
• The sound changes when I shift through N/R/D. Sometimes it keeps going, sometimes it stops after I put it in Park then back to D
• Intermittent, not every stop
• I don’t get any screeching; just a noticeable motorized whir that wasn't there before

My understanding is this is the electric transmission oil pump (and based off a comment I got from someone else on an FB group). My concern is that it showed up suddenly around 8K miles rather than being there from new and I've read the threads about the e-pump failures that end in full transmission replacements.

For those of you who've been through the pump failure: did it start as a quiet whir like this before it got loud? And for everyone else, do you hear this on your truck at stops, and how loud is it? Trying to figure out if mine is just normal operation I never noticed before, or the early stages of the known issue.

I am one (the one?) that had the transmission pump issue. Sorry, I can't figure out how to link threads but mine was named "new brake issue, not the screeching issue". because the symptoms started with full braking at red lights, I thought it was a brake issue.

The sound I heard, which started out intermittently, then became progressively more frequent and louder. It evolved from a whirring noise to a loud grinding noise. Only happened when in Drive at a complete stop with foot fully down on brake or in Park at start-up. The noise stopped as soon as I was in motion. Never in Reverse.

The defining symptom came about 2 weeks in; as soon as I let off the brake there was a strong "whump" which felt as if someone rear-ended me at 2-3 mph and the LC would jump forward. I wish I had or could have brought it in earlier than I did, but I travel a lot for business and my days at the home office were heavily booked during these developments. The capstone, and maybe necessary event for the dealer to read codes, was when the series of dashboard warnings started flashing all at once. The diagnosis and service was for a transmission pump failure.

I hope this was a one and done issue with my LC, but to be honest, I now look at it like lover that cheated on me once and I will have this in the back of my mind for quite a while. 20K on the ODO when this all went down.

 

[wpage]

I am one (the one?) that had the transmission pump issue. Sorry, I can't figure out how to link threads but mine was named "new brake issue, not the screeching issue". because the symptoms started with full braking at red lights, I thought it was a brake issue.

The sound I heard, which started out intermittently, then became progressively more frequent and louder. It evolved from a whirring noise to a loud grinding noise. Only happened when in Drive at a complete stop with foot fully down on brake or in Park at start-up. The noise stopped as soon as I was in motion. Never in Reverse.

The defining symptom came about 2 weeks in; as soon as I let off the brake there was a strong "whump" which felt as if someone rear-ended me at 2-3 mph and the LC would jump forward. I wish I had or could have brought it in earlier than I did, but I travel a lot for business and my days at the home office were heavily booked during these developments. The capstone, and maybe necessary event for the dealer to read codes, was when the series of dashboard warnings started flashing all at once. The diagnosis and service was for a transmission pump failure.

I hope this was a one and done issue with my LC, but to be honest, I now look at it like lover that cheated on me once and I will have this in the back of my mind for quite a while. 20K on the ODO when this all went down.

^^^ Wow, what a mystery resolved. Thanks for posting the resolution. Is the trans performing smoothly now??

 

[LC in the LOU]

I am one (the one?) that had the transmission pump issue. Sorry, I can't figure out how to link threads but mine was named "new brake issue, not the screeching issue". because the symptoms started with full braking at red lights, I thought it was a brake issue.

The sound I heard, which started out intermittently, then became progressively more frequent and louder. It evolved from a whirring noise to a loud grinding noise. Only happened when in Drive at a complete stop with foot fully down on brake or in Park at start-up. The noise stopped as soon as I was in motion. Never in Reverse.

The defining symptom came about 2 weeks in; as soon as I let off the brake there was a strong "whump" which felt as if someone rear-ended me at 2-3 mph and the LC would jump forward. I wish I had or could have brought it in earlier than I did, but I travel a lot for business and my days at the home office were heavily booked during these developments. The capstone, and maybe necessary event for the dealer to read codes, was when the series of dashboard warnings started flashing all at once. The diagnosis and service was for a transmission pump failure.

I hope this was a one and done issue with my LC, but to be honest, I now look at it like lover that cheated on me once and I will have this in the back of my mind for quite a while. 20K on the ODO when this all went down.

Yes, all is fine. That said, every time there is a gear shift that feels even slightly hard I get like a German Shepard with their ears on full alert and head cocked to the side listening.

 

[rjw250]

Yes,. The ICE was on initially.

Thanks a ton for doing this. Super super helpful. I honestly had not noticed the noise until a few weeks ago at 8K miles. Then, since it's intermittent - sometimes when the ICE is off, the truck is pretty much silent in any gear - I just assumed it was an issue. So many sounds... I really like the 250 and look forward to beating the crap out of it, but I do sometimes contemplate buying a 200 or 100...