4l80e slip yoke won't go in

[mccurrkm]

Hey guys...I had my drive shaft shortened and balanced last week and now when I went to put it back in...the yoke slides up onto the output shaft about an inch and then stops. It makes a bump sound like it is hitting something. I called the place that shortened it and they don't think they could have mixed up the yokes but I don't know what else it could be. It went on and off several times when I was measuring it to see how much it needed to be shortened. I have take it in and out several other times with no trouble.

What could it be?