Transmission Shifting Problems?

Thanks wayno.
I was thinking it might be the catalytic converter blocking the pipe so I took it to the muffler shop and sure enough the cat was rattling around plus the muffler was rusting through so we had the exhaust system replaced including O2 sensor, this made a big difference. It's pretty good now but I figure I may as well clean the valve body too. My buddy Phil the mechanic once said that it's often 2 things that are wrong since folks don't do enough preventative maintenance. Thanks for the thoughts, much appreciated :D