Now for the rest of the story. And I'm kicking myself royally every time I think about this!
I was fixated on finding a wheel spindle that exactly matched the one that was on the D170. What set it apart from the ones that I was finding online was that it only had one upward tab on it, which is probably some sort of turn limiter? By this time I had ordered and returned two different sets of wheel spindles that were supposedly for the D-170 from AMZ. Unfortunately both had come in with the wrong (2 tab) spindle and didn't look like the single tab wheel spindle that their ad pictures had shown. Had contacted two different JD dealers by this time and explained exactly what I was looking for (single tab) and they said didn't have what I needed.
Wife nagging me about getting her mower fixed so I decided to just bite the bullet and pay whatever the part would cost me if I could find a dealer/seller that carried it. Since the first two dealers had previously said the didn't have what I needed I called a third. They asked me for the serial number which I provided them. Yes! We have the part you need for the JD based on that serial number! I'll be right down I replied so off I go. Got there and they bring out a wheel spindle that has two upward tabs. Not the one I'm after I explained. At which time I was informed that they no longer make the the single tab spindle. It was replaced with the two tab version! So WHY didn't the two other dealers say that to begin with??? So I had returned two sets of AMZ wheel spindles already that I actually could have been used and had the tractor running in days instead of weeks.
In a crunch so I pay the $40 something, run home and install it. Fortunately the two front wheels fit the axle perfectly (the AMZ wheels are another story in themselves). Finally, success and wife will be thrilled to know she's back in business. Got around to explaining the whole dealer situation with the spindles, the tabs, etc. with her and how I could have used one of the two sets we had returned! That's when she tells me she never got around to returning the second set! That's when I really start kicking myself! If only I had know an hour earlier! That AMZ set came with TWO wheel spindles, all the washers, retainer clips, and the vinyl axle covers! And it cost less than $40 tax included. Could have rebuild the whole front end steering assembly for less than what I paid for that one piece from the John Deere dealer. Anyway, that's my sad story. Lesson learned. Hope your repair jobs go smoother! Will definitely be asking more questions if another repair comes up.