Nissan Repair: 1989 sentra auto trans left axle replacement, cv driveshaft, oppertunity

Question
Von; I have a 1989 Sentra that needed the driverside halfshaft replaced (cv's shot). I've taken out the old halfshaft & cv. I replaced with new(rebuilt) one but I can't seem to get it to seat & lock into the trans. I thought I had it but it leaked all the fluid out in a matter of minutes once started. Is there a seal in there I should have replaced? Is there a knack to getting the axle to seat & stay in the trans? I keep trying but I can always very easily pull it back out, shouldn't it lock into place? The locking ring is in place and looks ok.
Thank you for the oppertunity to ask.
  George

Answer
George,

The CV driveshaft clicks into place with a little force.  I have used a hammer and a large screwdriver on the edge of the inside joint before to get it in.  But, it could be a bad seal if the shaft is not popping out.  Also, if you bought a rebuilt unit and did not rebuild yours the c clip could be damaged and not have enough force to hold the shaft in.  I have seen where they sandblasted the shaft so much the clip was damaged and had to be replaced.