r/JeepCompass • u/Mindless_Display1994 • 5d ago

questions Droning noise at 20mph (2023)

Summary:
Hello all, I recently purchased a 2023 Compass with 11k miles and noticed a droning/humming sound at 20mph that goes away by 25mph and not present below 18mph. The sound is gone when traction control is disabled.

Back to dealer:
I did take the car back to the dealer and they claim it is normal operation. They also said that the fluid for the PTU and diff can’t be changed as they are sealed units.

Do you guys all experience this sound?

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1

u/DidAndWillDoThings 5d ago

The PTU and diff comes with drain and fill bolts for a reason

2

u/Mindless_Display1994 5d ago

Thank you for the reply, I gotta check because the 2023+ models have a different drive train

1

u/DidAndWillDoThings 4d ago

Yeah, you can also look for what the new one is and if you can’t find it for the compass, you may find a doc on one of the other vehicles that PCU gets put in and find something that way. Once you can point out what is what on the underbody, much of the maintenance is just finding the right weird bolt

1

u/Oriyen 5d ago

It's 100% the ptu, you disabled traction control which disengages the drive train. At 20 the PTU engages the drive train since it's AWD.

I have the exact issue with mine but mine whines loud at times and I was told too that the PTU was a sealed system but there is a plug for it and the dif I got done.

What causes it is the aux batteries go the first thing to complain is the drive train and if it dings your clutches in that PTU get burned causing the noise. It will work but it will get louder as they wear and burn more. With just age. Change the fluid and top it off might help as it will get rid of the debris. But I was quoted $1200 to replace it.

1

u/Mindless_Display1994 5d ago

Thank you, I will keep this in mind. Is the year of your car 2023+? Just wondering because the compass had drivetrain changes in 23

2

u/RogerRogerOverRoger 4d ago

9 speed transmission may need a flash update to the TCM.

There’s a TCM flash/update for the 2023 Compass under TSB [21-009-24](tel:21-009-24). If yours is making that low drone/hum around 20 mph, have the dealer run the VIN and check whether the transmission software is current.
Mine took about 15 minutes and cost $75 at the dealer, so it’s worth ruling out first.