Well, go back to Paul's commentary. If you had a bad motor mount and it changed the angles it could have introduced abnormal pressures resulting in the failure.
Funny you should mention this. Until January my wife had a 2002 Honda Odyssey. Apparently they have had transmission problems for years. While Honda's are good cars, clearly they should have done more with this one. I personally know 3 people with similar vintage Odyssey's with blown trans'. Google it and find a lot of problems.
Our first trans went out in 2010. Dealer wanted $5K we found another shop to do it for $2.4K. The car had about 135K on it at the time. 14 months later (of course it had a 12 month warranty) transmission goes out again. Since the aftermarket trans failed and the Honda dealer only offered a 12 month guaranty, we had to break down and buy a new one. We really were not ready to buy another car. We truly expected to get several more years out of that one, but then other age related problems were beginning to surface. The money we put on the trans equated about to $200 per month note.
Soo..... I your car is in otherwise good shape, and the cost is reasonable (I suspect that a Chryco trans will be less than a Honda with known problems) it may well be worth dropping a couple grand on one. Your alternative is to drop 10-15 times as much money on a new one. Now as to whether replace the output shaft, buy reman or have AAMCO do it - time is money but working on cars can be fun. If you have the time, I would probably put a reman in there. While the shaft clearly died, the rest of the trans should probably be overhauled because there may well be parts that are wearing after 125K. Since the biggest expense is pulling the trans/replacing it, get it tip top before putting it back. As to you vs AAMCO, time vs enjoyment vs money can be the guide.
