If I remember right there are 2 different shell sizes. Can you get a picture of the coupler with some measurements? The shell lengths I think are the only difference. If the coupler shell is worn internally you might want to look for a new shell and innards. To start though, post a pic!
Mopar NOS Plymouth Dodge STEERING COUPLER REBUILD KIT | eBay
Check this out, maybe it will have what you need.
