AW11SD37

Hi all,

I did a thorough search on existing topics, I'm sorry if I missed an existing answer.

First, a little background - I know I have a bad throttle position sensor, as the traction control is disabled and CEL is on. I just did a transmission fluid/filter change and it hasn't remedied the problem. I'm hoping it's due to the TPS but fear it may be a bad trans.

The car shifts as normal up to about 55 MPH or so. The issue arises when trying to pass this speed or when downshifting to pass or accelerate - the trans will very rapidly shift between 3rd and 4th, staying engaged in either gear for what feels like less than a second. Once you lift or slow down, the problem disappears. Any hope that this may be related to the TPS or does it sound like a bad transmission? Thanks in advance for any help. Please let me know if more detail is needed.