5HP18 Valve Body rebuild question

[shogun]

Hi Frank, do not touch the pressure regulator, just leave it as it is set by the factory. My wrenching buddy who is very experienced with trans work, also very seldom touches the large torx screw. Once we made some tests with a 4HP24 because even after full overhaul of the valve body, replacement of the filter and even trans system flushing the gear change still showed a bit of shock changes. Later we found out that this is caused by the different ATF we use, that was a Japanese ATF and that is apparently a bit harder than the OEM fluid.
To make changes, we had to take the oil pan off 3 times ! So first time we adjusted a bit on the torx screw too much, so back on the lift, ATF out, new adjustment, test drive and again the same procedure till all were happy with the shifting.
Baiscally, if you turn the torx just a quarter turn, that already makes a large difference.

one way check ball: this info I got from Whiskeychaser, he measured that, wait till he chimes in.
ATSG tells us:
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:
Before or after overhaul, vehicles equipped with ZF-5HP-18, may exhibit a "Bind-Up" condition in the Manual "2" position, 1st gear. 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. 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.

http://www.europeantransmissions.com....BMW/01-34.pdf

[Frank87]

Thanks for your speedy reply. I have read the ATSG manual. That is what got me to replace that check valve. Sadly, it also does not offer me a diameter.

I will leave that pressure regulator alone.