Are the torque converters identical for the 99-02 and the 03/04? I'm planning to put an 04 trans and transfer case into a 99 and have figured out that the rear trans mounts are in a slightly different spot (but workable) and this made me wonder if there are any other issues to be aware of. Specifically the torque converter because I plan to reuse the 99.

 

According to Ashcroft, the answer seems to be "it depends".
https://ashcroft-transmissions.co.uk/product/zf4hp22eh/
Read down at Torque Converter Upgrades.

The flex plates are the same.

 

Great, thank you. Both transmissions are the 24s so it sounds like a mix and match isn't a problem. The issue seems to be if you have a 22, then you won't fit the large torque converter, if you have it, in the bell housing.