Tranny problem

[BlackDak]

2001 Dakota, 4x4 QC, 4.7 auto

I have been having some tranny problems lately. I have noticed several times that the trans will lag before engaging from shifting from P to R, P to D, etc. It happens every day, about half the time.

I have also heard/felt it engage hard a few times. I am just curious what might be going on, if these are early signs of a known problem?

[BlackDak]

Anyone? I am sure someone has experienced this before...

[dirty-souf-rang]

i'm with you and it's worrying me...tranny's aren't cheap...i'd hate to
have to replace one

[01RTRC]

I'm experiencing the same symptoms with my '04 4X4 CC 4.7 & 545RFE during cold weather. I found this document published by GM on the GTO site explaining who electronic automatic transmissions enage. I think it also describes what is happening with the 545RFE.

Here is the post (sorry its kind of long):

Info - Engagement Time of Electronically Controlled Transmissions in General Motors Vehicles (Garage Shifts, Park to Reverse, Neutral to Drive, Neutral to Reverse, Park to Drive, Delayed Engagement) #03-07-30-007A - (Nov 4, 2003)
Engagement Time of Electronically Controlled Transmissions in General Motors Vehicles (Garage Shifts, Park to Reverse, Neutral to Drive, Neutral to Reverse, Park to Drive, Delayed Engagement)
2000-2002 Chevrolet Camaro

2000-2004 Chevrolet Corvette

2000-2002 Pontiac Firebird

2004 Pontiac GTO

2000-2004 All Light Duty Trucks

2003-2004 HUMMER H2

with 4L60-E (RPO M30) or 4L65-E (RPO M32) Automatic Transmission

This bulletin is being revised to add model years and models. Please discard Corporate Bulletin Number 03-07-30-007 (Section 07 - Transmission/Transaxle).

Park/Neutral to Reverse or Drive (commonly called garage shift) engagement times may be different from what many customers might be accustomed to, especially if they have recently traded for a General Motors' vehicle.

Normal Park/Neutral to Reverse or Drive engagement time will be in the vicinity of one (1) second if the automatic transmission fluid (ATF) is above 0°C (32°F) . When the ATF is colder than 0°C (32°F), the engagement time will become longer the colder the transmission fluid. A time limit factor cannot be placed on proper engagement times because the factors that affect transmission operation are many.

At the moment of engine start, for economy and emission requirements, the transmission line pressure is maintained at low levels. This allows a lower cold idle engine RPM (the colder the oil is, the higher the energy level (engine torque output) required to pressurize the oil).

When the driver moves the shift lever from "Park/Neutral" to "Reverse" or any "Drive" range, the following actions must occur for the powertrain control module (PCM) to determine at what pressure to control the transmission line pressure.

The module will look at the following items:

The voltage readings of the engine coolant temperature sensor (ECT).
The voltage reading of the transmission fluid temperature sensor (TFT).
Whether or not air conditioning is requested.
Movement of the shift lever and controls engine RPM based on the gear position selected. The module will adjust the engine RPM in response to the torque requirements needed to increase transmission line pressure.
When the module determines the status of the above items, the module will apply the appropriate signal to the PWM pressure control solenoid, thereby controlling the application of the required clutch(s) depending on the driver's selection.

Controlling transmission apply pressures allows the transmission to engage in a smooth manner, thus reducing the potential of abrupt/harsh engagement of the transmission.

All of the above actions happen very quickly; however, the resultant time interval may be approximately one second.

When determining if shift times are excessive, the exact conditions that the vehicle was in at the time the extended garage shift occurred must be duplicated. The following are several possible conditions.

Was the vehicle outside or in a heated garage?
What was the temperature of the environment at the time of the occurrence?
Length of time the vehicle sat unused, such as overnight or a weekend, etc.? A vehicle that has been driven to the service facility cannot be tested for this concern because the transmission, the engine oil and the coolant are no longer at the temperature they were when the customer experienced the condition.
No attempts to repair should occur unless the condition can be duplicated under the conditions the customer experienced.

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