whirring sound

I have a 2000 Bonneville SE, I have noticed recently that after the car has been driven for approx. 30 minutes, the shifting (automatic) is more noticeable, also most recently there is a humming or whirring sound that increases as the cars speed increases. It doesn't increase during acceleration of the engine, it increases with speed, even coasting and in neutral coasting. Any ideas?

Whine Noise in Park or Neutral, Service Engine Soon or Service Vehicle Soon Lamp Illuminates (Replace Drive Sprocket Support Bearing) #00-07-30-007A - (01/30/2002)
Whine Noise In Park Or Neutral, Service Engine Soon or Service Vehicle Soon Lamp Illuminates (Replace Drive Sprocket Support Bearing)
1999-2000 Buick LeSabre, Park Avenue/Ultra, Regal, Riviera

1999-2000 Chevrolet Lumina, Monte Carlo, Venture

2000 Chevrolet Impala

1999 Oldsmobile Eighty Eight

1999-2000 Oldsmobile Intrigue, Silhouette

1999-2000 Pontiac Bonneville, Grand Prix, Montana

with 3.4L, 3.5L or 3.8L Engine (VINs E, H, K, 1 -- RPOs LA1, LX5, L36, L67)

and Hydra-Matic 4T65-E Transaxle/Transmission (RPOs MN3, MN7, M15)

This bulletin is being revised to add the Chevrolet Impala to the models affected. Please discard Corporate Bulletin Number 00-07-30-007 (Section 07 - Transmission/Transaxle).

Condition




(1) Transmission ID Location
(2) SRTA Tag Location
(3) Hydra-Matic 4T65-E SRTA Tag
(4) Model Year (9 = 1999)
(5) Control Number
(6) Transmission
(7) Serial Number
(8) Julian Date
(9) Calendar Year (9 = 1999)
(10) Model
(11) Hydra-Matic 4T65-E ID Tag
(12) Model Year (9 = 1999)
(13) Line Built (1 = Line 1; 2 = Line 2; 3 = Line 3; 4 = Line 4)
(14) Transmission
(15) Julian Date
(16) Shift Built (A = First Shift; B = Second Shift; C = Third Shift)
(17) Model
(18) Serial Number in Base Code 31
(19) W = Warren Plant
(20) Hydra-Matic 4T65-E
(21) Model

Some owners of the above models equipped with a Hydra-Matic 4T65-E transaxle with a Julian Date prior to 0045 may comment on a whine noise in PARK and/or NEUTRAL or a Service Engine Soon or Service Vehicle Soon lamp that is illuminated. Upon investigation, a DTC P0741 or P0742 may be found.

Cause
The above condition may be due to drive sprocket support bearing fluting and/or bearing failure.

Correction
Replace the drive sprocket support bearing. Inspect the channel plate and drive sprocket for any abnormal wear, Turbine shaft for cut seals and/or nicks, and chain for excessive play due to failed bearings.


Important
When installing the new bearing, the part number MUST be visible (facing upward). Before installing the drive sprocket, lubricate the bearing assembly with J 36850 assembly lubricant.


Refer to the 4T65-E Unit Repair Section for the installation procedure.

Service Parts Information
Part Number
Description

24214158
Drive Sprocket Support Bearing


Parts are currently available from GMSPO.

Warranty Information
For vehicles repaired under warranty, use:

Labor Operation
Labor Time

K7522
Use Published Labor Operation Time

I have a 2000 Buick Century. Usually after hwy driving I get a similar whirring sound as well as very harsh upshifts from the 4T65-E transaxle. After the vehicle is shut off and sits for maybe 10 mins the condition disappears until next time (mostly a intermittant condition). Two transmission repair shops have recommended $2200 rebuilds, GM dealer replaced pressure control solenoid $600 which seemed to cure the problem for about a year and now the problem is reoccurring.