i used to have an AOD in my car, and after a rebuild i did the 1-d-1 shift ALL the time, i'd say half of the time i shifted it myself just cause i like to have control (and just incase a camaro comes out of nowhere
) i drove it like this for a year and about 10-15k miles before i swapped it for a T-5, it was still very strong when i pulled it out.
i worked at a ford dealer this summer and both of the tranny guys there (both big into stangs) said that it will burn out the overdrive band, if i remember correctly when you do the shift, it momentarily engages that band and therefore can burn it up easier. i'd say go for it anyway, i did and with a stock rebuild it held up perfect.
if you want to be sure, get a lentech valve body, or if you want complete peace of mind about the tranny, get a whole lentech AOD.
later
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88 Notch, B&M Ripper, 3.73's, Ported E7's, Explorer int. w/ ported lower, pulleys, 1.7RR's, BBK headers, off-road H-pipe, flowmasters, subframes, 65mm TB, March ram air ,MSD coil, U/L control arms, 155lph f/p, Crane Adj.FPR, Nitto drag radials, best 1/4--> 13.76@101.4 on a 2.17 60ft