Info - Changes for 2004 Model Year for 4T65E Transaxle - Internal Changes to Valve Body, Spacer Plate and Channel Plate and Touch Activated Power (TAP)

Important: This bulletin mainly deals with the features of the new Touch Activated Power feature of the 4T65E transaxle, which is only available on the supercharged Grand Prix. However, it is important for technicians to familiarize themselves with the differences between the TAP-equipped transaxle and the non-TAP equipped transaxle. There are several components of the transaxle that are unique to TAP. These components are NOT INTERCHANGEABLE with the same components on a non-TAP equipped 4T65E transaxle. If the correct parts are not used, serious driveability concerns could result.

The purpose of this bulletin is to introduce new features of the 4T65E transaxle for the 2004 model year.

Valve Body, Spacer Plate and Channel Plate

The internal changes to the 4T65E transmission are in the valve body, spacer plate and the channel plate. These parts are unique to the Touch Activated Power (TAP)-equipped 4T65E transmission. (TAP is only available on supercharged Grand Prix models.) A non-TAP transmission has a different valve body, spacer plate and channel plate. DO NOT MIX THE PARTS.

If incorrect parts are installed, there will be shifting concerns. Any test drives should include TAP-Shift™ operation.

The TAP channel plate and valve is shown on the left-hand side of the illustration. The non-TAP channel plate and valve is shown on the right.

The new TAP spacer plate has three notches in the lower right corner. The new non-TAP spacer plate has no notches in the lower right corner.

The new TAP-equipped vehicle also has different fourth clutch plates, with fiber on one side and steel on the other. A non-TAP vehicle will have normal fiber and steel plates for the fourth clutch.

The 2/1 manual band is made from a different material for TAP-Shift™ applications. This material will handle more stress than the normal 2/1 band in the other models.

The transaxle filter has also changed to improve oil pickup. The new filter will back service any past model 4T65E and its use is required on all Century, Regal, Impala, Monte Carlo and Grand Prix vehicles for 2004.

Performance Shifting with TAP-Shift™ (Available ONLY on Supercharged Grand Prix Models)

If the vehicle is equipped with the 3800 V6 supercharged engine, it may have a console gearshift with a MANUAL (M) position. The other gearshift positions available are PARK (P), REVERSE (R), NEUTRAL (N) and AUTOMATIC OVERDRIVE (D). These positions operate as they have in the past.

While in the MANUAL (M) position, the auto trans manual shift position switches, or paddles (located on the steering wheel), can be used to upshift or downshift the transaxle, under certain circumstances.

While in the MANUAL (M) mode, push either paddle once to upshift to the next gear. Pull either paddle once to downshift to the next gear.

To use the system, select MANUAL (M) while stopped, with the engine running. The vehicle will begin moving in first gear upon acceleration. For better control in icy or slippery conditions, the vehicle may start out in second gear, rather than in first.

The upshift indicator light on the instrument panel, or the upshift symbol on the Head-Up Display (HUD) (if equipped), is given as a prompt to use the TAP-Shift™ paddle.

These prompts to upshift as needed will be given throughout acceleration. If upshifting does not occur when prompted, the vehicle speed will be limited to protect the engine.

Press the accelerator quickly while driving in the highest gear to make the transaxle automatically downshift. The transaxle will also automatically downshift as the vehicle decelerates and comes to a stop.

When a paddle is pushed or pulled, a chime will sound when the vehicle cannot respond to a transaxle gear change. The system will not allow either an upshift or a downshift if the vehicle speed is too fast or slow, nor will it allow a start from third or higher gear. The MANUAL (M) gear can also be selected while the vehicle is already moving. The current transaxle position will continue to be displayed on the Driver Information Center (DIC) and HUD (if equipped). The transaxle upshifts and downshifts can be done using the TAP-Shift™ paddles as described previously.