need help rear end axle problem

I have a 1969 chevelle 12 bolt. I put in a new eaton 4 series posi carrier with timken bearings and yukon 30 spline axles. the problem is the axles just spin in the carrier. I bought the carrier on line and was told it was a 30 spline unit. I am wondering if it is possibly a 33 spline and that is why the axles spin. Is there a way to check the spline count with out taking it out of the housing?

It may be impossible to see the side gear when they are installed. The best way to check fit is to remove a side gear and axle and observe the fit.

Did you inspect the carrier and diffy when it was out?

I bought the posi carrier as a 30 spline unit and I bought 30 spline axles so I didnt think I would have to pre fit. I talked to the tech people at Eaton and they said some aftermarket companies sometimes put 33 spline gears in their units so I was wondering if anyone else had come across this. My axles are not bolted in yet because when the c clips were going to be put on there was deffinately a problem.