ok so i have a 4speed civic dx. the block is a d16a6 and the trans is off the d15b2 block. my cv joint is leaking. So i was thinking to just replace the whole axle. would a civic si 5 speed axle fit in my 4 speed transmission? just want to get the no or ok before i go buying one

 

yes, the Si axle will fit the 4 speed transmission - what you need to check is the other end of the axle where it goes into the hub - the 4-speed did not come in the DX cars - it came in the STD model which has smaller hubs than the DX/Si/LX/EX - if you have a STD model car, then you need Civic STD or CRX HF axles - count the splines on the hub end, 23 splines on the STD/HF, 26 splines on the Si/DX/LX/EX