5HP18 ball (one-way check valve) diameter needed

[shogun]

I hope someone can help, I need the ball diameter of ZF part number 1043 226 028 Valve, "D" CLUTCH ONE-WAY CHECK VALVE ASSEMBLY made of plastic, for that also a modified
"Replacement" ALLUMINUM CHECK VALVE is available http://www.europeantransmission.com/...MWtechinfo.htm

also in the parts catalog shown on page 27 of 42, Position # 51.200

BMW ZF-5HP-18 "BIND-UP" WITH SELECTOR IN MANUAL "2" POSITION, 1st GEAR
COMPLAINT: Before or after overhaul, vehicles equipped with ZF-5HP-18, may exhibit a "Bind-Up" condition in the Manual "2" position, 1st gear.
CAUSE: The cause may be, the plastic "D" Clutch One-way Check Valve assembly located in the Lower Rear valve body, shown in Figure 2, may be broken allowing the "B" Clutch (Reverse Input Clutch) to be on while the "D" Clutch (Low/Reverse Clutch) is on in 1st gear.
CORRECTION: Replace the "D" Clutch One-way Check Valve assembly , as shown in Figure 1, with a new assembly from ZF, or a new "Aluminum" check valve assembly offered by: Mario Aristides. Phone (305) 666-3544 or Fax (305) 666-8238.

"Original" PLASTIC CHECK VALVE ZF Number 1043-226-028
"Replacement" ALLUMINUM CHECK VALVE