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Jerry, Master Mechanic
Category: Pontiac
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Experience:  ASE Master tech. 30+ years mechanic, shop forman, service manager
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2004 pontiac grand prix 3800 4 speed auto started shifting

Resolved Question:

2004 pontiac grand prix 3800 4 speed auto started shifting harshly yesterday. Does so intermittently. 99,000 mi
Submitted: 7 years ago.
Category: Pontiac
Expert:  Jerry replied 7 years ago.

Hello and welcome to Just, Super mechanic here. About your vehicle.


There has been a service bulletin for that type of concern. Here is what it states.



A/T - Firm Shifts/Chuggle/No Decel Downshift/DTC P0742

Bulletin No.: 02-07-30-039F

Date: July 27, 2005


Firm Transmission Shifts, Shudder/Chuggle, Transmission Won't Downshift On Deceleration, Service Engine Soon Light Illuminated, DTC P0742 Set (Perform Diagnostics and Replace TCC PWM Solenoid)


2003 Buick Century, LeSabre, Park Avenue, Regal, Rendezvous
1999-2002 Cadillac Eldorado
1999-2003 Cadillac DeVille, Seville
2003 Chevrolet Cavalier, Impala, Malibu, Monte Carlo, Venture
1999 Oldsmobile Aurora
2001-2003 Oldsmobile Aurora
2003 Oldsmobile Alero, Silhouette
2003 Pontiac Aztek, Bonneville, Grand Am, Montana, Sunfire
2003-2004 Pontiac Grand Prix


with 4T65E Transaxle (RPOs MN3, MN7, M15, M76), 4T40E/4T45E Transaxle (RPOs MN4 or MN5) or 4T80E Transaxle (RPO MH1)

with PWM Solenoid Manufacturing Julian Dates Between 219 and 3048


This bulletin is being revised to change the statement of Transmission Release Pressure to Torque Convertor Clutch (TCC) Release Pressure. Please discard Corporate Bulletin Number 02-07-30-039E (Section 07-Transmission/Transaxle).


Some customers may comment that the transmission shifts hard, a shudder/chuggle is felt on deceleration or the Service Engine Soon (SES) light is illuminated.

A technician may find DTC P0742 set.

Customers with 4T80E transaxles may also comment on a "bump" feeling at approximately 61-68 km/h (38-42 mph) when they lift and then tip into the throttle. There may also be a concern of whine noise in 3rd or 4th gear with or without the Service Engine Soon light/message displayed and with DTC P0742 set.



Important: This test is not applicable to the 4T80E transmission. Instead, replace the TCC PWM solenoid on vehicles with a 4T80E transmission using published procedures for the vehicle being serviced.


Perform one of the following diagnostics:

^Test drive the vehicle with the Tech 2(R) installed, Monitor TCC Release Pressure. The Status will be YES until TCC applies and then the display will read NO. If during acceleration the status remains NO and the upshifts are harsh and during deceleration the vehicle shudders during downshifts, suspect the TCC PWM solenoid.


^With the Tech 2(R) installed in the vehicle, start the engine. Build the vehicle on the Tech 2(R). Apply and firmly hold the service brake. Place the transaxle in D4 and command Drive 3 with the Tech 2(R). If the engine stumbles and/or stalls, suspect the TCC PWM solenoid.


Replace the TCC PWM solenoid using published procedures for the vehicle being serviced.




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