45RF vs 45RFE vs 545RFE

The trans in my 2000 WJ 4.7L 4x4 blew up today.

Most threads here say the 2000 has the 45RF, but Wikipedia says the 1999-2000 4.7L WJ uses the 45RFE, with the 545RFE being the same trans, reprogrammed in 2001 to use all 5 speeds (or really 6 speeds with the extra 2nd gear).

From Wikipedia: "1999 and 2000 model year WJ owners can have their 45RFE transmission's programming flashed to enable the extra gear as both transmissions are physically the same."

I guess my question is, how can I tell if I have a 45RF or a 45RFE, and are they interchangable? There are a lot more 45RFE's from 03s and 04s out there.

Check out Allpar, here's a start for you:

http://www.allpar.com/mopar/transmissions/545RFE.html

You can check with the stealership about the reprogramming...they'd probably be the ones that have to do it. Seems like Wiki is right, or very close to it.

That's a great resource. Thanks.

I forgot to update this thread, but it turns out it was not the tranny, but the front differential. The mechanic was really confused when it came in and wasn't really sure what was wrong. Apparently there was a leak in the housing and it heated up, blowing out what little fluid was in there and then it seized up. Once it cooled down it drove ok again, but you could tell the gears took a beating because it was very hard to turn the front driveshaft. I just replaced the front axle assembly and it's running great.