2008 Mazda 3,2.3, AT, PO720 code
 

Hey everyone,

First post so have a little patience with me. I am not a mechanical or proactive person. Not a lot of preventative maintenance on my ride. Too broke.

Anyway, Tranny having issues while driving. All speeds. It is having difficulty staying in one gear. Engine light will come on and AT light comes on... the lights will go off after it is shut off. I had a shop run the codes. It came up with PO720 VSS circuit malfunction. They recommended these two sensors, (FN-21-551 & FN01-21-550).

My question is...Before I change those out should I change the fluid and filter ? The vehicle has 170k on it. Never had fluids changed. Color of fluid is dark. Not red
Am I too far gone ?

Thanks for the feedback. David

OK, Going to have the fluid and filter changed.
Question, I have heard that "flushing it", instead of draining it,could do further damage.
Thoughts ?

Do you resolve your problem. I changed the two sensors but the problem was a bad TCM, I repair the TCM problem solve.