5HP18 Valve Body rebuild question

[whiskychaser]

I have ordered my overhaul parts from them. Even they said the vbk is no longer available.

I have used: http://eshop.original-teile.de/index.php?

To order valve body parts piece by piece. All original ZF.

I have not bought one for a while. You would think they would remove it from the catalogue.

[632 Regal]

@Regal:
I think your 2-3 shift problem had more to do with slammed teeth on the F drum and a bad F drum glide bearing. Because:
- From 2-3 the G clutch disengages
- From 2-3 the F clutch engages
The friction plates IN the G drum that lock into the F drum will, over time, slam the teeth on the F drum meaning it will take a little longer before F engages / disengages
The bad F drum glide bearing inside the F drum will cause the F piston to move in and out at a slower rate

This is a typical early 5HP18 fault. You will not nessecarily notice slippage or jerks as the engine indeed stops revving during shift moments. However, when the engine does rev, it will put torque on the G friction plates who will put that torque on the damaged F drum. The result is some slippage since those plates do not instantly grab-hold or release. I have opened up multiple "18" boxes and all show slammed teeth on drum F from plates belonging to drum G.

Mine was the 94 530, and the EAT chip was the problem. After changing it out I went another 110K miles before I sold it with no trans issues.

[Frank87]

Update:

Started clean with a completely overhauled transmission.

When using a valve body in which I only worked on the main channel plate (cleaning + replacement of balls and orifices) the transmission shifts like new except for the 1->2 shift.

When using a valve body in which I worked on the main channel plate AND where I have also replaced ALL springs with OEM ZF new ones, the transmission shifts like new except my 2->1 downshift gives me a slight jerk as described in this topic.

This means I am dealing with a valve body related issue. The valve body I talked about previously in this topic is a different valve body. I have 3 valve bodies:
1: Valve body of which the main channel plate has been done, gives me a not-so-smooth 1->2 shift, solenoids show proper ohm resistance
2: Valve body of which the main channel plate and most springs have been done, gives me a 2->1 jerk, solenoids show proper ohm resistance
3: Valve body of which the main channel plate and ALL springs have been done, gives me a 2->1 jerk, solenoids show proper ohm resistance

Valve body 2 and 3 are definately the better valve bodies for all other shift points when compared to valve body 1.

The 2>1 does NOT jerk if:
- The car is in S mode
- The car upshifts to 2 gear but never goes higher than 2. So 1->2 and then 2->1.

Which means the jerk is there if:
- The car is in D mode and has shifted to 3 or higher

The jerk is more apparant the more braking power you apply. An emergency stop from 50 to 0 gives a clearly noticeable jerk. Rolling the car from 30 to 0 gives a less noticeable jerk (but still there)

This 2->1 thing is the final piece of the puzzle!

[632 Regal]

Did you try disconnecting the brake light switch yet? Could be some issue with the check control unit that enables engine braking while slowing down however it shouldn't have anything to do with the 1-2 upshift.

[Frank87]

It must be valve body related. Old sloppy valve body gives me a good 2-1 downshift. Completely overhauled valve body gives me a bad 2-1 downshift.

[632 Regal]

It must be valve body related. Old sloppy valve body gives me a good 2-1 downshift. Completely overhauled valve body gives me a bad 2-1 downshift.

Which leads me to question other partially related items.

[shogun]

Which paper gasket did you use between the valve body plates and which one was originally installed? Did you check the new one by cross checking it with the old one coming out of the valve body? identical holes and channels? Usually I lay one over the other to compare.
There are 2 different ones. According to my expert info from a ZF repair shop there are
gasket 1056 327 100 5HP18 old version
gasket 1056 327 110 5HP18 new version

I bought both of them as I do that more often on other cars and according to this expert, the new gasket can replace an old gasket (originally installed) but a old gasket version cannot be installed in a valve body originally equipped with a new version.

Same is with the 5HP30
paper gasket 1055 327 093 5HP30 old Version
paper gasket 1055 327 102 5HP30 new Version

[Frank87]

I used the newer gasket. I ordered 5 of both part numbers "just in case" as they dont cost anything.

The older gasket has 1 big hole where the filterneck connects with the valve body.
The newer gasket has 1 big hole where the filterneck connects with the valve body and a small rectangle shaped hole right next to it.

I have used that newer style gasket with 2 big holes more often in the past without issues.

[Frank87]

For those of you who are interested in the outcome, I had 2 of my 3 valve bodies measured by a specialist who has 3D equipment. The 2 valve bodies who shift excellent but have a 2-1 jerk both suffer from bore wear in the exact same housing. Bore wear leads to too little or too much pressure causing bad shifting. He said there are generally 3 options:
- Fabricate the exact same piston but oversized from a block of anodized metal to compensate bore wear
- Buy new housings and fit the old pistons and springs (pistons were fine)
- Buy a used valve body which measures correct pressures in every mode on his test bench

Option 1 would cost $$$ due to the price of the anodized material and the engineering work in measuring the old pistons, estimating the increase in bore and refining the raw material

Option 2 would cost $$$ due to single housings for valve bodies being expensive. ZF prefers to sell entire valve bodies and take back your old used one

Option 3 was a cheap and easy option as he had access to all kinds of vendors we individuals don't. He came up with the exact same used valve body from a 088 transmission, measured it, slotted in the improved selector piston and sold it to me as the solution.

I fit this valve body and after a thorough reset of the entire car (DME, AGS etc.), the transmission started shifting better and better.

The box is now excellent and the 2-1 jerk was explained by bore wear in valve housings.

Since I fit a used valve body, it will last perhaps up to 150.000km instead of 300.000. I already put about 20.000km on the box so in 30.000 km, after a good 50.000, I will probably do an oil change and may even fit a factory new valve body to see if that makes the box shift even better. This would cost me about 1000 euros. The fine shifting valve body I have now, will be held in reserve. I am going to overhaul the 5HP18 box that came out of the car after my previous overhaul as I plan on buying a 3.0 V8 sedan or touring for my girlfriend in about a year or so. That car can then be fitted with this overhauled box with the used but "ok" valve body. This makes it possible to specifically look for a car with autobox damage meaning the price goes down.

[shogun]

Excellent info, Frank. Thanks a lot.
I might add, we always test the solenoids + pistons inside the bore with ATF when the valve body is disassembled, if it moves softly. We also polish the solenoids in such case as well as the bore. Usually helps to overcome the problem. Otherwise you have to get hold of another used valve body and use the parts needed for swopping. That is an old youtube from 7 years ago when we were still learning.
https://www.youtube.com/watch?v=iRN1jwEkydg
http://3.bp.blogspot.com/-BifeYG6d2h...0/P1180784.jpg
http://1.bp.blogspot.com/-17n8VCgTdJ...0/P1180786.jpg