67757 comes up as part number for the carrier

72944=4.11

E229 I believe is the date code, but my book is 74 and doesn't give the code for yours

4911, this may be the ratio also, are you sure about the 9, book shows a letter in the 2nd position

C1979, not sure on this one. My book is 74 and your rear is possibly newer than that.

So, its an 18k lb rear with 4.11 high. Is it useable to you now that you have some basic info?