Vibration around 1200rpm

[tazwatson]

Hello All,
I have a 2023 with the 5.7 eTorque and 8 speed. At between 1125 and 1300rpm I get a vibration/Hum that sounds very deep base. I have done some miner troubleshooting to figure out the specific timing of the sound. First time I ever heard it I thought it was a very deep base line in a song on the radio (I have surround sound Alpine and it sounds great) but it kept getting louder and stayed at the same frequency. This never happens when the trans is cold. I have noticed it when the trans temp gets above 177 degF. I have also noticed it does not matter if it is in ECO or not. This noise is very annoying when driving at just the right RPM. I am not sure if this is a Torque converter chatter or valve body. At about 1200 rpm in 6th, 7th or 8th gear with the trans hot is when I notice it. It seems to be right at the point where the torque converter should unlock or where the shift point is. The truck is less that 1000 miles from 10,000 mile service so I will be discussing with the dealer when it is serviced. I just wanted to see if anyone else has had or noticed this issue. Are there any TSB's that reference anything like this noise?

 

[vincentw56]

Hello All,
I have a 2023 with the 5.7 eTorque and 8 speed. At between 1125 and 1300rpm I get a vibration/Hum that sounds very deep base. I have done some miner troubleshooting to figure out the specific timing of the sound. First time I ever heard it I thought it was a very deep base line in a song on the radio (I have surround sound Alpine and it sounds great) but it kept getting louder and stayed at the same frequency. This never happens when the trans is cold. I have noticed it when the trans temp gets above 177 degF. I have also noticed it does not matter if it is in ECO or not. This noise is very annoying when driving at just the right RPM. I am not sure if this is a Torque converter chatter or valve body. At about 1200 rpm in 6th, 7th or 8th gear with the trans hot is when I notice it. It seems to be right at the point where the torque converter should unlock or where the shift point is. The truck is less that 1000 miles from 10,000 mile service so I will be discussing with the dealer when it is serviced. I just wanted to see if anyone else has had or noticed this issue. Are there any TSB's that reference anything like this noise?

I assume you have your stock exhaust. What you describe sounds like exhaust drone to me.

 

[tazwatson]

I have not changed the exhaust. Something else to add is that if I am in tow Haul mode I can't seem to replicate Have only tried that once. I could hear the drown and pushed the tow haul button. The sound stopped for a sec. then came back for a sec. then was gone. Still running in same gear and same rpm. I don't think it is exhaust because at the same rpm when trans is cold I do not hear it.
Thank you for the reply and the additional ideas.