I wrote most of this in response to Drew Sagan, in a thread that wasn't really about this issue. When I read back over it, I figured it need a thread of its own.
The first part of the puzzle is in Appendix 1D of the NWT Reference Bible. They list all "237 places where the name Jehovah occurs in the main text of the New World Translation of the Christian Greek Scriptures." These "renderings" are based on various sources classed as "J" references. These instances really cannot be classed as renderings at all, since no actual translation of the Greek occurred. They are examples of interpretive paraphrasing.
These "J" references are from "translations" from Greek into Hebrew spanning many years. But even in these cases, it is patently clear that the Hebrew from Greek was mistranslated if the name YHWH was inserted into the Hebrew, as it could not possibly have appeared in the Greek from which translation was supposedly occurring. For myself, this argument logically nullifies any appeal to the authority of the "J" references on this point.
However, there is a further nullification line of reasoning. In the Introduction of the Rbi8-E (the NWT Reference Bible) we find the Bibliography for the "J" references. Herein, we discover that the oldest "J" reference used as an authority is J2 and is dated to 1385. This is many years into what the WTS calls the "Great Apostasy", but according to them, the plainly incorrect translation from Greek into Hebrew completed in the year 1385 should be used as an authority for imitating the mistranslation. This is completely illogical on many levels.
Closer examination of Appendix 1D reveals that manuscripts J1, J2, and J4 are ONLY used with Matthew. J3 is ONLY used with Matthew and Hebrews. J5 and J6 are ONLY used with Matthew, Mark, Luke, and John.
Which leaves only ONE "J" reference as primary support for most of the remaining mistranslations. J7, Christian Greek Scriptures in 12 languages, including Heb., by Elias Hutter, Nuremburg, 1599. I say "most of the remaining" because sole reference for some of these instances comes from "translation" work done since the year 1800.
In the case of Colossians 3:13, the mistranslation is supported solely by J23, a work published in 1975 (the year the world should have ended, again). In Colossians 3:22, the support for the mistranslation comes from J18 (1981) and J22 (1942). Colossians 3:9 is supported by J18 (1981) and J23 (1975).
Ephesians 6:8 is supported only by J22 (1942) and J24 (1863).
By far the majority of mistranslations have no older support than J7 (1599), which itself, in turn, served as an authority for the translators of most (if not all) of the other "translations" into Hebrew.
There is no logical defense for the WTS' position on this blatant mistranslation of Greek into English. Especially in the case of 1 Corinthians 7:17, where they admittedly served as their own authority in deciding to mistranslate the Greek text into English (see Appendix 1D). But, there is an illogical defense. As usual.