Does anyone how I can tell what kind of catalytic converter is on my 98 GMC Sierra 1500? Meaning monolithic, pelletized, etc.? I know approximately nothing about auto repair. The truck is a 4x4, 5.0L V8, gas engine.... I just bought this truck last week, and before I got it, I had it checked out by a mechanic (at Midas) who said that the catalytic converter was broken because it rattled. (Don't worry--I got a dicount on the price to fix it). But I was just reading about this online, and I've seen articles that say if a pelletized converter DOESN'T rattle, then it's broken, but a monolithic converter is broken if it DOES rattle. I also saw that you can do emissions tests to find out for sure, but I don't know if this guy did that. I'm just a little nervous about him using rattling to diagnose the problem, before I shell out hundreds of bucks. I did a google search to try to find out what kind of converter I have, but came up with zilch. Also, the guy at Midas said it would be $200, and I just talked to a more local mechanic, and he said it would be $379 plus $68 for labor. Do either of those prices sound fishy to you? I'd just go back to Midas, but it's about 1.5 hours away, and the other guy is 5 minutes away and has a good reputation. Thanks!