can a Touque converter being bad or a valve body stop your car from going into third

my car is acting really nuts once it ***** to third i get no movement

and when it heats up i have to turn the car off then mack on to move it it will shift normally till third again

strange problem?

 

Mods? Should be throwing a code that'll help nail it down.

 

pretty much stock i upgraded to 3.42's and a rumbler exhuast

 

There are lots of A4 tranny codes - did/is the SES light on? First thing I'd do is get the PCM scanned for any current or history codes.