2002 Honda Civic Fluid leakage and seal problems

I have a 2002 civic EX manual transmission. I purchased the car a little over a year ago, after about 3 months it started popping out of 5th gear because it had a transmission leak. Which after replacing the axle seals turned out to be that fluid was leaking through the axle somehow. So I replace the axle and the leak was fixed but 5th gear and reverse had been ruined from driving without fluid. I purchased a used transmission and had it installed. Now about 2 months later it has a bad axle seal. Could it be that there is something wrong with the car that is causing the axle seals to go bad or with the transmission I bought? Is it possible or likely that something is wrong with the car that is causing axle/seal problems?