My Maxx was built in late April, and while I don't understand the necessity for the "Julian" dating (just give us the build dates, sheesh!!). I'd venture a guess that this covers vehicles built from about 1/17/04 to 5/16/04. I definitely have this occurring on my vehicle.
Here's the text:
"ASI Resolution - Growl or Howl Type Noise From Transmission/Engine Compartment During Light to Moderate Acceleration from a Stop (Replace Drive Link, Drive Sprocket and Driven Sprocket) #04-07-30-021A - (Jul 2, 2004)
2004 Chevrolet Malibu, Malibu Maxx
2004 Oldsmobile Alero
2004 Pontiac Grand Am
Built After January 16, 2004
with 4T45E Automatic Transaxles (RPO MN5) Built Between Julian Date 4016 and 4126 and
3.4L or 3.5L V6 Engine (VINs E, 8 - RPOs LA1, LX9)
This bulletin is being revised to include a repair procedure and parts availability information.
Please discard Corporate Bulletin Number 04-07-30-021 (Section 07-Transmission/Transaxle).
Condition
Some customers may comment on a growl or howl type noise during light to moderate acceleration from a stop. This noise is load and engine RPM sensitive and will occur between 1500 RPM to approximately 2300 RPM. The noise is most noticeable in first and second gear. The noise may dissipate prior to the 1-2 shift, but will be noticed again in second gear depending on the load and engine RPM. The pitch of the noise will change during the 1-2 shift.
Cause
The noise is due to the new 5/8 inch drive link assembly being at a resonant frequency during certain driving conditions.
Correction
Important
Only RPO MN5 transaxles built between Julian date 4016 and 4126 have 5/8 inch drive link assemblies. Refer to Transmission ID and VIN Derivative Location, SI Document ID #760312 for Julian date location information.
Follow the service procedure below to replace the 5/8 inch drive link and sprockets with a 7/8 inch drive link and sprockets."