Help engine continues to heat up after it's off.

I have a 99' Grand Am GT 3.4L 72,000 miles. I need a little help, my engine heats up after I turn the car off; the highest I've seen it go after I turn it off was 3 marks past 200. But when this happens the transmission for some odd reason starts to mess up. I thought that I'd fixed this with replacing the Cat converter (it was clogged). But now the problem with it heating up after it was off has started back up. I don't know why but I have a feeling that my muffler guy might have messed up and put the wrong Cat converter on, is there a different converter for 6-cyl and 4-cyl?

Sometimes during these hot days we hav been having, an engine will heat up a little after shut down.
But it shouldnt rise that much. This is due to the fans not running to cool it down.
Are the fans working when the car is running ?

And I think the cats are different. the V6 is bigger.

Yes I belive the fans are running I checked them before I had the Cat replaced and they were fine. I will check them again but I think they are fine. I figured that the Cat would be bigger I'll just have to go back by and see wich one they put on. Would the smaller Cat cause the car to heat up that much or at all?

i have a 2002 GT and it does the same thing, runs 1-2 marks over 200 when driving normal but after shutdown and sitting for a few minutes its up to the third. it seems normal to me.

Well it would be normal for me if it wasn't for the fact that when I go to drive the car again while the temp is up the Tranny messes up, it doesn't like to go into drive right away. It will kind of slip for the first min. or two.

Well it would be normal for me if it wasn't for the fact that when I go to drive the car again while the temp is up the Tranny messes up, it doesn't like to go into drive right away. It will kind of slip for the first min. or two.

it is normal that the engine heats up after shut down.

78silverbird, hav you had the transmisison serviced, ever?

Most tranys will act funny when they get hot, though the sliping could be due to a low fluid level or thier could be other issues with the trans.
A fluid and filter "chnage" will do the trany good, thats for sure.