CV Axle installation

I recently have been working on this 08 Toyota Sienna for a customer of mine and I'm in the middle of changing the cv axle. The old one is out and the new one is ready for installation, but I can't get the cv axle to fully mate with the transaxle. It will go in most of the way but stop at a certain point and leave about an inch of the inner shaft hanging out of the transaxle. I don't wanna sit there and beat on this thing all night and ruin a brand new unit so any advice would be very helpful. I know these cv axles utilize that inner "pop" ring as I have heard it been called where you kinda have to pull and give it a quick pop to get the old one out which worked perfectly. I have worked with these style before in other vehicles and they usually pop right in but this one has been getting to me. Thank you for your help