I just bought an 04 TL with 70k miles. All of the sudden when I press the brake when in 4 or 5 gear it downshifts and revs really high. Also, sometimes when shifting from 2 to 3 or 3 to 4 is shakes before it shifts. Is this a pressure switch problem or trans problem? It seems to be getting worse fast. Any help greatly appreciated!

 

Sounds like your transmission is in its way out.
Try replacing the 3rd & 4th press switches and do a redline ATF 3x3 and see if that improves it.

 

Thanks! I am going to get the repair done and il let you know