2000 C5 Drivetrain Noise - Whirring

[zappac5]

My 2000 C5 with automatic transmission is making a whirring (sounds like metal on metal?) sound at 1400 rpm. As I crossover this threshhold either increasing or decreasing, I can hear the sound. If I drive at that rpm constantly I can hear it. Above or below that rpm, no issue. Sounds like it is coming from the year of the car. Not speed dependent, only rpm dependent. I can be in neutral and rev the engine up to that rpm and not hear in, it has to be in gear. The car has approx 75000 miles on it. Any ideas/thoughts would be appreciated.

[c4c5specialist]

Hi there,

I would suggest removing your accessories drive belts and see if the noise is still there. If so, you probably have a pulley or component with a bad bearing.

Have you had any work done recently????

Allthebest, c4c5

[zappac5]

No work done recently.
I have popped the hood, rev'ved up the engine - no unusual sounds from the engine compartment.
It has to be in gear and really sounds like it is coming from the rear.

[c4c5specialist]

Hi there,

If its in the rear, then the noise would change pitch based on vehicle speed.

Do you feel anything from the ebrake lever or the shifter. If the noise was from the differential, going on and off the gas would change the noise.

Allthebest, c4c5

[zappac5]

No nothing with the brake or shifter. It is automatic transmission, but I have tried the different gears D, 1,2,3 and it has nothing to do with speed. RPM only, as I speed up or ease off the gas thru approx 1400 rpm is when it occurs creating the whirring metal on metal sound. No noise below or above that rpm.

Maybe it is some time of harmonic or vibration that occurs at that rpm. It is almost like two cymbols that you held close together facing each other and spun them in opposite directions (best analogy that I can come up with). I am at a loss.

[froggy47]

I'm with Paul thinking pulley. Look at then all carefully with a light & mirror and see if there are any rub marks, CK balancer.

:)

Go under if you can to look also.

[c4c5specialist]

HI there,

OK, then based on what you have said in your last post, it may be the torque tube bearings.

Unfortunately, at this point, the only way to diagnose this is to get under the car and disconnect the torque tube first to see if it goes away. If it does, then you reconnect the torque tube and disconnect the torque converter from the torque tube and then reevaluate.

If you have a lift, that would be your best course of action.

Allthebest, c4c5

[urbs4]

hey zappaC5 ... did you ever get this noise diagnosed ? I am hearing the same thing on my 99 w/ 162K miles. your description is exactly what I am hearing. I'm convinced its in the rear, and only a specific rpm level. 'whirring' is a spot-on description. If you got it figured out - can you let me know what you found ? thanks !

[Z0_RICK]

Does the noise decrease as the car warms up ?
Does it make the noise about 10 secs after startup?