Either I've missed it – or it hasn't been addressed. I am building my transmission on my 1984 Pontiac Firebird. I am upgrading the pump from a 7 vane to a 13 vane… Is there any downfall to doing that – any problems that doing that could cause?

 

no downfall to swapping the 13 vane rotor in-pumping capacity will not change much,mostly the 13 vane was introduced to reduce pump moan at lower RPM .There are no pins or anything to hold the pump halves concentric when it is reassembled,so you will have to make sure the halves are concentric before the bolts are fully tightened.

 

Thank you very much

 

I've heard the 13 vane rotor is easier to break than the 10.
Nothing wrong with upgrading. The OEM changed to 10, then to 13 across millions of vehicles, so it's a proven change.

 

Do not install the 13 vane setup in a 700R4. The volume will be down. The 13 vane setup is more than "just the rotor". The slide is different and the back half of the pump is different also in the 1997 and up 4L60E pumps. On the back half of the pump, the entrance and exit oil slots are in different locations and the 13 vane slide has the same matching locations. Only go to 10 vane setup if the rotor is worn at where the inner hub meets the torque converter. 7 & 10 vane setups are interchangeable. Always add the TransGo steel rings and priming spring here to prevent parts breakage. They come in standard 5,500 and lower WOT shifts or the Hi-rpm for motors going over 5,500 rpm at WOT. They are known as "No Yo Yo" in the industry. To use the 13 vane setup in a 700R4 would require that you do the modifications to the back half of the pump as in the 4L60E.