I know this is an old post, but thought I would share for others considering this. Even though the TH400 transmission mount will work, it has a set back. The bottom of the 2004R pan will sit on the crossover and I couldnt get the transmission mount to bolt up without spacers (washers) because of a gap between both of them, So you have to elongate the holes to help, but you still will not be able to pull the trans pan without removing the x over so I decided to get an after market x over. Also, if you try and use the TH400 transmission cooling lines, you will need to bend them to fit. These two items caused me to change these two items since no one ever posted anything about this. Could be my car, but I have recently found post by other owners, by a google search stating the same thing. Hope this helps others out... still worth it if your want your engine to run lower RPM's