A4 Tranny slippage?
06-16-2002 | 04:39 PM
#1
Thread Starter
Registered User
Joined: Jun 2001
Posts: 30
From: Union City, CA
A4 Tranny slippage?
My transmission has been slipping once in a while, I'm not sure if that's the correct term to describe it. It seems that when it's supposed to be shifting, it seems like it goes into neutral, and then it shift after a slight delay. The shifts are getting a little softer too. Should I take it to a dealer?
06-17-2002 | 02:47 AM
#4
Registered User
Joined: Apr 2001
Posts: 441
From: Hawaii
Have you checked your fluid level.
------------------
2002 SS #3442 Navy blue metallic A4 160 T-stat/TB by-pass/SLP fan swich/DMS SFC's/K&N FIPK/Magna Flow Cat-Back/GMS MAF/SLP Y-pipe/
(Very first run stock with 750 miles)
60ft 2.162 1/8 8.782@83.48 1/4 13.553@102.93
Best to date:
60ft 2.041 1/8 8.612@84.28 1/4 13.326@104.39
------------------
2002 SS #3442 Navy blue metallic A4 160 T-stat/TB by-pass/SLP fan swich/DMS SFC's/K&N FIPK/Magna Flow Cat-Back/GMS MAF/SLP Y-pipe/
(Very first run stock with 750 miles)
60ft 2.162 1/8 8.782@83.48 1/4 13.553@102.93
Best to date:
60ft 2.041 1/8 8.612@84.28 1/4 13.326@104.39
06-17-2002 | 01:36 PM
#5
Registered User
Joined: Mar 2002
Posts: 1,711
From: Canadian West Coast
You certainly don't have any mods or enuf mileage that would suggest any obvious problem. As Drew states, you might check the tranny fluid levels (low fluid levels will cause this), and if they look normal, I'd call a good dealer for warranty work (if you have one...). There should be no slipping with your tranny and I suspect it will be getting worse.
06-18-2002 | 01:00 PM
#6
Registered User
Joined: May 2001
Posts: 1,122
From: Memphis, TN, USA
A/T - Slipping/Missed Shifts Diagnostic Tips
File In Section: 07 - Transmission/Transaxle
Bulletin No.: 01-07-30-043
Date: December, 2001
INFORMATION
Subject:
Diagnostic Tips for Slipping or Missing Second, Third and/or Fourth Gear
Models:
2001-2002 Chevrolet Camaro, Corvette
2001-2002 Pontiac Firebird
2001-2002 Chevrolet and GMC C/K Pickup and Utility Models
(Silverado, Sierra, Suburban, Tahoe, Yukon, Yukon XL)
2001-2002 Chevrolet and GMC G-Van Models (Express, Savana)
2001-2002 Chevrolet and GMC M/L-Van Models (Astro, Safari)
2001-2002 Chevrolet and GMC S/T Pickup and Utility Models
(S10, Sonoma, Blazer, Jimmy)
2002 Chevrolet and GMC S/T Utility Models (New Style) (TrailBlazer, Envoy)
2002 Cadillac Escalade
2001-2002 Oldsmobile Bravada
Recently, a study was completed to determine the causes of slipping/missing 2nd, 3rd or 4th gear in the 4L60/4L65-E transmission family. This study was conducted using transmissions which were determined by dealership technicians as having a slipping/missing shift. The transmissions used were from vehicles with less than 19,000 km (12,000 mi) and the slipping/missing shift condition was verified during a test drive by dealership personnel before the transmission was removed from the vehicle. Eight items were found to cause the majority of the slipping/missing shift concerns. These eight items are listed below in the order of frequency that they were found.
^ Chips in the servo feed oil passage, orifice # 7 in the spacer plate.
^ Cut forward clutch piston inner seal.
^ Cut 3/4 clutch piston outer seal.
^ Input housing orifice cup plug blown out.
^ Input housing cracked or broken.
^ Mislocated valve body to spacer plate check ball(s).
^ Case damaged at the 2nd clutch apply piston pin bore causing the pin to drag/stick in the bore.
^ Input housing air bleed orifice cup plug with a check ball that does not seal.
In addition to the above items, a misadjusted shift cable has been found to cause these types of concerns. When attempting to correct a slipping/missing second, third or fourth gear, the items listed above should be inspected as possible causes. It is also important to reference the appropriate Service Information for additional possible causes of these concerns.
File In Section: 07 - Transmission/Transaxle
Bulletin No.: 01-07-30-043
Date: December, 2001
INFORMATION
Subject:
Diagnostic Tips for Slipping or Missing Second, Third and/or Fourth Gear
Models:
2001-2002 Chevrolet Camaro, Corvette
2001-2002 Pontiac Firebird
2001-2002 Chevrolet and GMC C/K Pickup and Utility Models
(Silverado, Sierra, Suburban, Tahoe, Yukon, Yukon XL)
2001-2002 Chevrolet and GMC G-Van Models (Express, Savana)
2001-2002 Chevrolet and GMC M/L-Van Models (Astro, Safari)
2001-2002 Chevrolet and GMC S/T Pickup and Utility Models
(S10, Sonoma, Blazer, Jimmy)
2002 Chevrolet and GMC S/T Utility Models (New Style) (TrailBlazer, Envoy)
2002 Cadillac Escalade
2001-2002 Oldsmobile Bravada
Recently, a study was completed to determine the causes of slipping/missing 2nd, 3rd or 4th gear in the 4L60/4L65-E transmission family. This study was conducted using transmissions which were determined by dealership technicians as having a slipping/missing shift. The transmissions used were from vehicles with less than 19,000 km (12,000 mi) and the slipping/missing shift condition was verified during a test drive by dealership personnel before the transmission was removed from the vehicle. Eight items were found to cause the majority of the slipping/missing shift concerns. These eight items are listed below in the order of frequency that they were found.
^ Chips in the servo feed oil passage, orifice # 7 in the spacer plate.
^ Cut forward clutch piston inner seal.
^ Cut 3/4 clutch piston outer seal.
^ Input housing orifice cup plug blown out.
^ Input housing cracked or broken.
^ Mislocated valve body to spacer plate check ball(s).
^ Case damaged at the 2nd clutch apply piston pin bore causing the pin to drag/stick in the bore.
^ Input housing air bleed orifice cup plug with a check ball that does not seal.
In addition to the above items, a misadjusted shift cable has been found to cause these types of concerns. When attempting to correct a slipping/missing second, third or fourth gear, the items listed above should be inspected as possible causes. It is also important to reference the appropriate Service Information for additional possible causes of these concerns.
06-18-2002 | 01:07 PM
#7
Registered User
Joined: May 2001
Posts: 1,122
From: Memphis, TN, USA
One more:
=====================
A/T - Poor Performance/SES Lamp ON/DTC P0757 Set
File In Section: 07 - Transmission/Transaxle
Bulletin No.: 01-07-30-038
Date: December, 2001
TECHNICAL
Subject:
DTC P0757 Set, SES Lamp Illuminated, Poor Performance of Transmission, Transmission Slipping
(Clean Transmission Valve Body and Case Oil Passages of Debris)
Models:
1999-2002 Chevrolet Camaro, Corvette
1999-2002 Pontiac Firebird
1999-2002 Chevrolet and GMC C/K Pickup and Utility Models
(Silverado, Sierra, Suburban, Tahoe, Yukon, Yukon XL)
1999-2002 Chevrolet and GMC G-Van Models (Express, Savana)
1999-2002 Chevrolet and GMC M/L-Van Models (Astro, Safari)
1999-2002 Chevrolet and GMC S/T Pickup and Utility Models
(S-10, Sonoma, Blazer, Jimmy)
2002 Chevrolet and GMC S/T Utility Models (New Style) (TrailBlazer, Envoy)
1999 Cadillac Escalade
1999-2002 Oldsmobile Bravada
Condition
Some customers may comment on any of the following conditions:
^ The SES lamp is illuminated.
^ No 3rd and 4th gear.
^ The transmission does not shift correctly.
^ The transmission feels like it shifts to Neutral or a loss of drive occurs.
The vehicle free wheels above 48 km/h (30 mph). High RPM needed to overcome the free wheeling.
Cause
The most likely cause is chips or debris plugging the bleed orifice of the 2-3 shift valve. This will cause the transmission to stay in 2nd gear and return to 1st gear when and/or if the PCM attempts a 3-4 shift. DTC P0757 code may also be set if the 2-3 shift valve were stuck or hung-up in its bore. Inspect the 2-3 shift valve and the 2-3 shuttle valve for free movement or damage and clean the valves, the bore and the valve body passages.
Correction
The 1-2 and 2-3 shift solenoid valves (also called A and B solenoids) are identical devices that control the movement of the 1-2 and 2-3 shift valves (the 3-4 shift valve is not directly controlled by a shift solenoid).
The solenoids are normally-open (not energized electrically) exhaust valves that work in combination to shift the transmission into four different forward gears. Opening and closing the exhaust valves within the solenoids redirect the transmission fluid, hydraulically moving shift valves and the corresponding shifting of the transmission gears.
The PCM energizes (turns On) or de-energizes (turns Off) each solenoid by either grounding or removing the ground to the solenoid through a quad driver (switch) within the PCM. This allows current flow through the coil winding of the solenoid which causes movement of the internal plunger, blocking or opening an internal orifice.
The 2-3 shift solenoid (SS) valve controls the fluid flow acting on the 2-3 shift valves.
The vehicle speed sensor (VSS) assembly provides vehicle speed information to the PCM. The VSS assembly is a permanent magnet (PM) generator. The PM generator produces a pulsing AC voltage as rotor teeth on the transmission output shaft pass through the sensor's magnetic field. The AC voltage level and the number of pulses increase as the speed of the vehicle increases. Output voltage varies with speed from a minimum of 0.5 volts at 100 RPM of the transmission output shaft to more than 100 volts at 8000 RPM of the transmission output shaft. The PCM uses the pulsing voltage to determine vehicle speed. The PCM uses the vehicle speed signal to determine shift timing and TCC scheduling.
Estimated gear ratio is calculated by the PCM, using the estimated torque converter turbine speed (estimated turbine speed is calculated from engine speed and engine torque) divided by the transmission output speed (VSS). The estimated gear ratio is displayed on the Tech 2 as a range of 0.00:1 to 8.00:1.
P0757 will be set, stored within the PCM, when the PCM has detected an incorrect shift pattern when both of the following occur:
^ The PCM commands third gear for 1 second or more.
^ The engine torque is 68-542 N.m (50-400 lb ft).
^ The engine speed is greater than 1.44 time the TCC slip speed.
^ The PCM then computes the estimated gear ratio and then compares the estimated gear ratio with what the third gear ratio should be (1.00:1). If the computed gear ratio is in the range of 1.575:1 to 1.825:1, the PCM has determined the transmission is not in 3rd gear. It is, in fact, in second gear hydraulically.
^ All conditions are met for more than 2 seconds.
AND
^ The PCM commands fourth gear for 1 second or more.
^ The engine torque is 0-542 N.m (0-400 lb ft).
^ The engine speed is greater than 1.13 time the TCC slip speed.
^ The PCM then computes the estimated gear ratio and compares the estimated gear ratio with the expected fourth gear ratio (.696:1). If the computed gear ratio is in the range of 1.8:1 to 3.26:1, the PCM has determined the transmission is riot in 4th gear. It is, in fact, in first or second gear hydraulically.
^ All conditions are met for more than 2 seconds.
The PCM then takes the following actions:
^ Records the operating conditions when the DTC was set, so it may be retrieved with the Tech 2 from the Freeze frame and Failure Records.
^ Illuminates the malfunction indicator lamp (MIL).
^ Commands 3rd gear.
^ Commands maximum line pressure.
^ Will no allow TCC engagement.
^ Freeze 3 transmission shift adapt functions.
^ Stores the P0757 as a history trouble code when the ignition is shut off.
=====================
A/T - Poor Performance/SES Lamp ON/DTC P0757 Set
File In Section: 07 - Transmission/Transaxle
Bulletin No.: 01-07-30-038
Date: December, 2001
TECHNICAL
Subject:
DTC P0757 Set, SES Lamp Illuminated, Poor Performance of Transmission, Transmission Slipping
(Clean Transmission Valve Body and Case Oil Passages of Debris)
Models:
1999-2002 Chevrolet Camaro, Corvette
1999-2002 Pontiac Firebird
1999-2002 Chevrolet and GMC C/K Pickup and Utility Models
(Silverado, Sierra, Suburban, Tahoe, Yukon, Yukon XL)
1999-2002 Chevrolet and GMC G-Van Models (Express, Savana)
1999-2002 Chevrolet and GMC M/L-Van Models (Astro, Safari)
1999-2002 Chevrolet and GMC S/T Pickup and Utility Models
(S-10, Sonoma, Blazer, Jimmy)
2002 Chevrolet and GMC S/T Utility Models (New Style) (TrailBlazer, Envoy)
1999 Cadillac Escalade
1999-2002 Oldsmobile Bravada
Condition
Some customers may comment on any of the following conditions:
^ The SES lamp is illuminated.
^ No 3rd and 4th gear.
^ The transmission does not shift correctly.
^ The transmission feels like it shifts to Neutral or a loss of drive occurs.
The vehicle free wheels above 48 km/h (30 mph). High RPM needed to overcome the free wheeling.
Cause
The most likely cause is chips or debris plugging the bleed orifice of the 2-3 shift valve. This will cause the transmission to stay in 2nd gear and return to 1st gear when and/or if the PCM attempts a 3-4 shift. DTC P0757 code may also be set if the 2-3 shift valve were stuck or hung-up in its bore. Inspect the 2-3 shift valve and the 2-3 shuttle valve for free movement or damage and clean the valves, the bore and the valve body passages.
Correction
The 1-2 and 2-3 shift solenoid valves (also called A and B solenoids) are identical devices that control the movement of the 1-2 and 2-3 shift valves (the 3-4 shift valve is not directly controlled by a shift solenoid).
The solenoids are normally-open (not energized electrically) exhaust valves that work in combination to shift the transmission into four different forward gears. Opening and closing the exhaust valves within the solenoids redirect the transmission fluid, hydraulically moving shift valves and the corresponding shifting of the transmission gears.
The PCM energizes (turns On) or de-energizes (turns Off) each solenoid by either grounding or removing the ground to the solenoid through a quad driver (switch) within the PCM. This allows current flow through the coil winding of the solenoid which causes movement of the internal plunger, blocking or opening an internal orifice.
The 2-3 shift solenoid (SS) valve controls the fluid flow acting on the 2-3 shift valves.
The vehicle speed sensor (VSS) assembly provides vehicle speed information to the PCM. The VSS assembly is a permanent magnet (PM) generator. The PM generator produces a pulsing AC voltage as rotor teeth on the transmission output shaft pass through the sensor's magnetic field. The AC voltage level and the number of pulses increase as the speed of the vehicle increases. Output voltage varies with speed from a minimum of 0.5 volts at 100 RPM of the transmission output shaft to more than 100 volts at 8000 RPM of the transmission output shaft. The PCM uses the pulsing voltage to determine vehicle speed. The PCM uses the vehicle speed signal to determine shift timing and TCC scheduling.
Estimated gear ratio is calculated by the PCM, using the estimated torque converter turbine speed (estimated turbine speed is calculated from engine speed and engine torque) divided by the transmission output speed (VSS). The estimated gear ratio is displayed on the Tech 2 as a range of 0.00:1 to 8.00:1.
P0757 will be set, stored within the PCM, when the PCM has detected an incorrect shift pattern when both of the following occur:
^ The PCM commands third gear for 1 second or more.
^ The engine torque is 68-542 N.m (50-400 lb ft).
^ The engine speed is greater than 1.44 time the TCC slip speed.
^ The PCM then computes the estimated gear ratio and then compares the estimated gear ratio with what the third gear ratio should be (1.00:1). If the computed gear ratio is in the range of 1.575:1 to 1.825:1, the PCM has determined the transmission is not in 3rd gear. It is, in fact, in second gear hydraulically.
^ All conditions are met for more than 2 seconds.
AND
^ The PCM commands fourth gear for 1 second or more.
^ The engine torque is 0-542 N.m (0-400 lb ft).
^ The engine speed is greater than 1.13 time the TCC slip speed.
^ The PCM then computes the estimated gear ratio and compares the estimated gear ratio with the expected fourth gear ratio (.696:1). If the computed gear ratio is in the range of 1.8:1 to 3.26:1, the PCM has determined the transmission is riot in 4th gear. It is, in fact, in first or second gear hydraulically.
^ All conditions are met for more than 2 seconds.
The PCM then takes the following actions:
^ Records the operating conditions when the DTC was set, so it may be retrieved with the Tech 2 from the Freeze frame and Failure Records.
^ Illuminates the malfunction indicator lamp (MIL).
^ Commands 3rd gear.
^ Commands maximum line pressure.
^ Will no allow TCC engagement.
^ Freeze 3 transmission shift adapt functions.
^ Stores the P0757 as a history trouble code when the ignition is shut off.
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