Fluid Pressure Directed in Preparation for a Shift to Fourth Gear

WARNING: This page is about a different variant/trim than selected.

2-3 Shift Valve: 2345 fluid is routed through the 2-3 shift valve (371) into the 345 fluid circuit.
X-4 Ball Check Valve: 345 fluid is routed through the X-4 ball check valve pocket. In some transmission models there is a ball check valve present which would force 345 fluid through orifice #25.
3-4 Shift Valve: 345 fluid is routed to the 3-4 shift valve (345) where it is blocked by the valve in preparation for an upshift to fourth gear.