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Q: Around 2000 rpm, car shifts erratically from 4 to 3 gear, code comes up as Bad Shift Solenoid C

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If I reset CEL and keep truck around 2000 rpm, it shifts and maintains speed fine, however as I go above said rpm the trans drops out of fourth into third, then if I let off the throttle it will shift back to fourth. If I don't let off throttle, the truck stays in third and the CEL comes on, and the code says shift solenoid c is faulty. I replaced the solenoid, filter, and fluid but it still does same thing. It was a good runner until that popped up out of nowhere, what could it be? It's hard to keep those speeds while on the expressway. Please help, thank you!

My car has 179546 miles.
My car has an automatic transmission.

Hi there, thanks for writing in. Based off your details, you could possibly have a problem with the transmission front pump seal that will not let the lock up torque converter go into overdrive, and may set codes for overdrive. The possible code is P0628 or P0741. I recommend having the front pump seal inspected, and if it’s damaged, replace front pump and converter.

If you’d like help with this issue, consider having one of our certified mechanics come to your home or office to inspect and diagnose this issue for you.

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