I changed both solenoids, transmission filter and fluid, vehicle speed sensor and the output speed sensor. I only need to change the input sensor, but I want to change both input and output speed sensors because the output speed sensor I changed was from the junkyard and so to be sure I'd like to change both input and output speed sensors. I still have the slipping problem when I take off (I have to go easy when I take off so that it can work right) and it still shifts hard between gears. What can you tell me that I need to know? Thank you
My car has 107000 miles.
My car has an automatic transmission.
Hi, thanks for writing in. Let’s go over some basics. The transmission is shifting to all 4 gears. This means the solenoids are working. The solenoids get there command from the PCM. The PCM uses the speed sensors to know when to shift, good. If there is is a circuit problem in the solenoids or speed sensors, a hard fault is stored and the transmission goes into default mode, 3rd gear only. The only test you need to do now is to hook up a pressure gauge to measure line pressure. This will indicate if there is a mechanical problem. Worn bushings, hard lip seals, and worn frictions all lead to slipping. The computer will compensate by raising line pressure, giving you hard shifts. The 4L30 is not known for longevity. I rebuilt one for my own Rodeo earlier this year. That is likely what it needs. If you would like help, consider having an expert automotive technician from YourMechanic come to your home or office to inspect and diagnose this issue for you, and make or suggest any repairs as needed.
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