I gotta replace the pump in my '95 4l60E and I had bought a billet 10 vane rotor to go in the new one. I just got the new pump apart and it has a 13 vane pump in it. Is there any internal differences on a 13 vane pump when compared to a 10 vane pump?

Also, would I be able to just drop the 10 vane rotor in this thing or do I need to go back to the trans shop and get a 10 vane pump?

 

If yours is an original 1995 pump then it would have come with a 10 vane setup. If it has been rebuilt, then a 13 vane setup could have been added, or an original 13 vane pump from a 1997 and up was installed. You would have to look at the back side of the pump and see if it has a "13V" on it. If it does, it is an original 13 vane setup. With an original 13 vane setup, you could go with the 10 vane billet rotor and the 13 vane slide. The slide has to be in excellent condition to be reused, and you should go with new vanes. If this a hi-rpm setup (over 5,500 rpm shifts) then I would add the TransGo Hi-rpm steel rings and single priming spring now while it is apart. The 10 vane setup will not be as quiet as the 13 vane unit, but thats it.