Resizing Teflon Seal Ring Automatic Transmission
 

The rebuild of my 722.317 Transmission continues. Today as I went to reassemble the secondary pump, the cutoff piston did not want to slide into its bore. Repeated attempts and a closer inspection finally revealed the issue(s). The leading edge of the bore where the piston goes has a sharp machined edge. The combination of the new split teflon seal and the sharp edge was causing the seal to catch on the edge. I had to resize the seal by compressing it all around and I had to slightly deburr the edge. The attached pictures show the details.

Afterwards, the piston slides right in with a little TransJel.