UPDATE: Any guys using the search to find out the diameter here it is:
On 98 3.0 2wd the pipe by the muffler is 2' and its the same after the muffler.
If your buying a after market muffler buy the 2 1/4 size and use the following if your doing it yourself:
2, 2.25" to 2" adapters
1, 2" to 2" muffler extension (you will have to cut down)
2, 2.25" clamps and 3, 2" clamps
This worked great and it sounds mean!! Heres the website I found the info on with pics, this explorer had the same setup as my 98:

http://www.explorerforum.com/forums/...d.php?t=182514

I installing a new muffler today, I remember somebody telling me 2 1/4 was the size I needed. So I bought to 2 1/4 adapters and the new muffler was 2 1/4. Well after I cut the old muffler off I saw the adapters did not match up with the pipe but did work with the new muffler.

Im going back up to buy the correct stuff soon as sombody can correct me on the right size adapter to buy. Thanks

1998 3.0 2wd

 

2.5"

 

If 2.5 to loose then go with 2 3/8

 

thanks for the replys, so the stock pipe on a 98 3.0 is 2.5 or 2 3/8? They are the same on both ends where the stock muffler used to be?

 

They do make reducers in 2 3/8s,that what it took to put a new cat on my beater.

 

Or get a pipe expander to make it work.

 

on my '01 4.0, right after the last cat, is 2.5, then the spring flange thing, then 2", then muff, then 2", then the tip(last 5" or so) is enlarged to 2.25. Thats what mine was stock.

 

mines the same as above

 

well I was out buying the right part and got home and 2.5 is way off (way to big). I just saw th posts here while I was gone, Im headed to te 24 autozone intown to try yet again. Im going to try a 2inch.

 

Heres a drawing of what my set-up is. Im confused on what size adapter to buy for both sides. I bought the wrong adapter yet again. Im having a hard time.
[IMG][/IMG]

 

okay...those adapters are a little trucky....there's a ID and OD measurement. I believe you'll need a 2.25" ID and a 2.00" OD adapter for this to work. 2.25 to slip into the muff, and a 2" to slip over the exhaust.

 

Your dead on Fx, I did a update at the top for the future keyword searchers.

 

well i cant say what size i had for my 2000 but from the header back i put 2.5" pipe into a high flow cat and 2.5" all the way to the 50 series delta flow flowmaster and dumped right at the bed