5HP18 Valve Body rebuild question

[Frank87]

Car: 530iA Sedan Euro
Transmission: ZF5HP18 "088"

I am rebuilding a spare "088" 5HP18 transmission. I already did all the work on the driveline. I plan to rebuild the valve body next week. I will then slot the valve body into my current transmission (which runs excellent by the way) to ensure I did not screw up on the valve body so that, when installing the complete transmission + valve body, I know that when a problem arises, it's in the driveline. I have 2 problems:

Problem 1: I do not know the diameter of the one way check ball.
There is a one way check valve used when the manual "2" position is slected with the lever. I have ordered the part from ZF but I only get the plant pot, spring and cap. No ball. I also want to start using an aluminum ball but I do not know the diameter. I have looked in various forums and came across the same question asked by Shogun. A reply was that the ball measured about 4.56mm but afaik that was a ball from a used valve body so it may already have worn down to 4.56.

Problem 2: I do not know how to calibrate the pressure regulator correctly.
The 5HP18 repair manual states that the pressure regulator needs to be adjusted after any work done to the valve body or internals of the transmission. The repair manual does not say what or how to do this. I have not touched the pressure regulator yet. The pressure regulator is located in the solenoid block. It has a large torx screw on it. Any info on how to calibrate this piece is welcome.

Any help or advice would be great. I have a large amount of photo's to share on how to strip the driveline. I will upload these somewhere on this forum.

[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.

[shogun]

ZF 1043 226 028 VALVE, ZF 1043 226 028 VENTIL looks like you can order it from Germany http://en.technikexpert.net/zf-1043-226-028-valve.html
5HP18 Valve Body – Valve Housing Groups, position item # 51.200, part number 1043 226 028, Valve 1 piece, used in Stuecklistennummer 1056 000 081/087/088

[Frank87]

I have ordered that part but it comes WITHOUT a ball. It just gives me the plant pot, spring and cap.

[whiskychaser]

I have ordered that part but it comes WITHOUT a ball. It just gives me the plant pot, spring and cap.

Hi Frank
Where are you and where did you order the part from? No joy with the contact in Shogun's post? If you are in the US you could try Eriksson Industries. Pretty sure somebody on a Russian website had about 100 of them so probably has one or two to spare:-) That is assuming online translation worked. Will try to find the link if you still need it
You are in a Catch 22 situation with the pressure regulator. If it is worn, it can potentially blow your D/G clutch. But if you take it apart to inspect it, you screw up the settings. You are probably best leaving it alone as Shogun says. I don't believe you can bench test it at home but you should be able to test the line pressure at the tappings when it is installed

[Frank87]

I will have to think this through then. Do I need any unique tools for pressure testing? I can probably get common gauges and stuff.

When I adjust that valve body, turning that screw clockwise will increase or decrease pressure? And what exactly are the results of modifying the pressure + or -?

[whiskychaser]

The pressure regulator isn't a simple on/off device - the TCM tells it how far to open/close depending on operating conditions. If you want to do it at the tappings, details will be in Bentleys. The consequences of getting it wrong? Too much and you could blow the clutch drum. (Its not the D/G as I mentioned above - that's on a 5HP18 - it will be the F but it goes for the same reason) Too little and there is not enough to apply the clutches. BTW, they did come out with a modified pressure relief valve for the 5HP30. It has a larger shoulder than the original and may be worth a look.

[Frank87]

I am doing a 5HP18. I have removed all parts of the solenoid block to be able to thoroughly clean everything. I have not touched the large Torx nut. I reinstalled everything exactly the way it came out.

Sadly, the internet does not offer any guide on the pressure system at all. I can consult the Bentley manual to test pressure but I would still not know how to properly adjust it.

[whiskychaser]

I am doing a 5HP18. I have removed all parts of the solenoid block to be able to thoroughly clean everything. I have not touched the large Torx nut. I reinstalled everything exactly the way it came out.

Sadly, the internet does not offer any guide on the pressure system at all. I can consult the Bentley manual to test pressure but I would still not know how to properly adjust it.

Unfortunately, that is the case. Unless you have the odd $31k to spare and want to buy one of these :-) :
http://europeantransmissionscom.x-sh...me.php?cat=628

In practise, you are only going to be able to find out what the line pressures are. Are you installing the valve body kit?