'91 Park Ave Half shaft

I am having trouble replacing the half shaft on my "91 P.A.. The old one came out witout any signifigant trouble however the remaned one only slips on a small distance and becomes jammed to the point that it must be wedged back off. The spline looks good on both the transaxle and the half shaft. What am I missing? could be there be an issue with the spring clip that is on the transaxle shaft? Do I need to lube the shaft for easy fit any Ideas?

Thanks for any help you may provide.

A slight twist on the output shaft may be hard to see and is a fairly common problem. You can use a three point fine file to clean up the splines on the shaft, then use some moly wheel bearing grease (not too much) on the splines before installing the half-shaft. In addition, install a new seal, and lubricate the outer half-shaft hub before installing.