I just did a B16A swap in my 97 civic hatch and bought 99-00 si axles and the passanger side just wont set up on the trans and pop out when I drove it what axle do I need on the pasanger side it seems like the driver side is ok though

 

Maybe you didn't get the axle set ring to lock into the differential. How much gap was there between the inboard joint and the differential case? There should only be about 1/8 inch.

 

Thanks for the reply um...it has maybe two inches roughly I check to make sure it was locking and it did.