Guy here who sold the dana 30 to OP! The D30 was pulled off my DD LJ after I installed my HPD30. It had about 60k miles on it, not 40k. There should be nothing wrong with it as before I took it off it was driving me from school and back. Reason I swapped axles was because I found a good deal on a built HPD30. Also remember that if you ever need to use the spare axle shaft I gave you, to take off the unit bearing on the end. The unit bearing on the spare shaft is toast.
Also nice meeting you, hopefully Ill see you around on some runs posted on the CA section of the forum!