does a transmission that is removed from original car last out side or does it corrode with you know being outside of the car .got a some sitting around they look same as when i bought em but by the time come id have to used then will they be good ?
My guess would be that as long as any seals exposed to the elements held up and kept water out of the transmissions they may be OK, but they'll need to be gone over before trying to use them in anything. (In most cars transmissions get a good splashing from driving in inclement weather anyway but things like torque converter and axle seals are not exposed.)
not enough information here to answer your question. How long is it being stored? Where is it being stored and what is the climate. Are the transmissions new or used? What surface treatments were used? How is it packaged? etc...
If you didn't already know, yes of course steel corrodes when exposed to air and moisture.
