Why do I have bad shifting on my 4L80E?
Why do I have bad shifting on my 4L80E?
In addition to erratic shifting, the trans control program will default to backup shifting mode if you drive it long enough with this bad sensor, and as a result line pressure through the valve body will be boosted to maximum value, creating harsh shifting.
Where is the Transmission Control Module on a 4L80E?
The 4L80E Transmission system is equipped with a computer called the Transmission Control Module (TCM), located in the left/rear passenger seat compartment which interprets, ana-lyzes and records electronic signals from sensors and switches located on the engine, brake pedal, and transmission.
How does the clutch work on a 4L80?
It is this clutch that provides the mechanical coupling from the engine to the transmission. The Computer commands this clutch through the torque converter solenoid. The TCC solenoid actuates pilot pressure and sends it to the pump. The pump (in short) puts the pressure on this plate that some call a piston.
What causes OD on a 4L80 diesel?
Since your transmission has 200Ks on it the problem is likely that the valve sleeve bore has worn. When the Torque converter Solenoid strokes the piston the transmission fluid leaks past when hot. The hydraulic signal get so weak that it will no longer activate the control valve within the pump thus kicking in OD.
What are the symptoms of a bad transmission solenoid?
Another common symptom of a problem with the downshift solenoid is a vehicle that experiences late downshifting. If the downshift solenoid fails or has an issue, the vehicle may experience late shifting when slowing down. The transmission may stay engaged in a higher gear for an extended period of time when it should be downshifting.
What causes a transmission not to shift?
A lack of fluid or dirty fluid would cause the transmission not to shift properly. We recommend checking for transmission fluid loss, and using BlueDevil Transmission Sealer if the system is low. If the fluid looks dirty, you may want to have a transmission system flush performed and refill it with clean fluid.
What causes shifting problems?
A worn clutch disc is the most likely cause of hard or difficult shifting. Check the clutch pedal free-play adjustment to insure the clutch is released completely. A manual transmission needs to spin down in order to shift smoothly. Excessive spin down time is more noticeable when shifting into reverse.
Why would a car shift hard?
Hard shifting may be caused by a slow sensor or one that is transmitting the wrong signals from the engine. A faulty speed sensor may be to blame for reporting that vehicle is running more slowly or more quickly than it actually is.
When to replace shift solenoids in GM 4L60-E?
TIP 4: If your transmission is slipping, replacing the shift solenoids, even if they’re fried will not solve the slipping issue. The 4L60-E transmissions uses several solenoids and sensors to control/activate its 4 gears.
What causes no reverse on GMC Sierra 4L60E?
No Reverse – Most of the time reverse won’t engage when the clutches are worn out. It may be (but is less likely) that the sun shell went bad as well. There’s a whole article on this site dedicated to diagnosing no reverse in the 4L60E.
In addition to erratic shifting, the trans control program will default to backup shifting mode if you drive it long enough with this bad sensor, and as a result line pressure through the valve body will be boosted to maximum value, creating harsh shifting.
TIP 4: If your transmission is slipping, replacing the shift solenoids, even if they’re fried will not solve the slipping issue. The 4L60-E transmissions uses several solenoids and sensors to control/activate its 4 gears.
No Reverse – Most of the time reverse won’t engage when the clutches are worn out. It may be (but is less likely) that the sun shell went bad as well. There’s a whole article on this site dedicated to diagnosing no reverse in the 4L60E.
What happens if there is no reverse shift?
Splitting the circuits electrically is a very basic step in the “No Reverse” shift concern diagnosis. Electrically controlled transmissions generally have a built-in safety program that prevents the transmission parts from breaking based on a rolling speed shift reference during the reverse engagement.
