Valve Body Rebuild ZF 4HP22EH.   By Badsect0r

Mission Statement:
Perform a complete valve body rebuild on a ZF 4HP22EH transmission with E9 (7 pin, 4 solenoid) valve body, in order to improve shift quality, and eliminate some anomolous behaviors of this notorious transmission.

Early forms of this transmission were first introduced in 1980 and it was produced through to 2003.  It can be found in many vehicles, including those made by BMW, Jaguar,  Maserati, Puegeot, Volvo, Porsche,  and Landrover.

There are many versions of this transmission in general use.  The one described here is from my 1992 BMW E34 535i pictured above.  It is an electronically and hydraulically controlled version of the transmission.  The valve body is the later E9 type.  It uses 4 solenoids and has a 7 pin plug. 

Although the specifics described below do not apply to all versions of the valve body, the principals and procedures are often similar for other versions of the transmission and in some cases other transmissions entirely.  Therefore, although the following article is written with a specific audience in mind, it should also be of some use to a much wider audience of "Do It Yourself" car enthusiasts as a whole.

Legal:
Any information contained herein should be used for educational purposes only.  I do not condone it's use by unauthorised or unqualified persons in the servicing of their own or anybody else's vehicle.  As such I absolve myself from responsibility for any damages or losses caused by the use of said information.  Use of this information is done so at the sole risk of the person and/or persons using it.

© Badsect0r 2013 - This work is copyright. You may download, display, print and reproduce this material in unaltered form only (retaining this notice and imagery metadata) for your personal, non-commercial use within your family or organisation. All rights reserved.

Tools:
Pencil
Scissors
Multimeter
5mm Allen Key
10mm Socket (3/8” Drive)
Ratchet (3/8” Drive)
6” Extension (3/8” Drive)
Torx 27 bit (3/8” Drive)
30mm Socket (1/2”Drive)
Ratchet (1/2” Drive)
3” Extension (1/2” Drive)
Universal Joint (1/2” Drive)
Small Magnetic Flat blade Screwdriver
2 x Large Plastic Tub
Razor Blade
Funnel (small end about 10mm in diameter)
Precision Torque Wrench
Trolley Jack and Axle Stands, or Ramps, or Hoist

Parts & Consumables:
Pan Gasket
Main Valve Body Gasket
Transmission Filter
1 x Jar Vaseline
9 Litres of Dexron III Automatic Transmission Fluid
12 Spray Cans of Degreaser
2 x Rolls of Paper Towel
4 x Lint Free Cloth
1 x Large Newspaper/Advertising Catalogue
1 x Cardboard box (about the size of a shoebox)
Sticky Tape

Reference Material:
Corresponding repair manuals can be bought from ATSG , also check out reference material from ZF

Acquisition of Parts:
Initially I tried ZF Australia. They were willing to sell me a full transmission rebuilt kit only, AU$179.00. I asked them if they could supply the main gasket for the valve body by itself, they had no stock and no ETA.

After talking to a few people at local transmission workshops I was pointed in the direction of Motospecs. They were able to supply 4 different versions of the main gasket. Three were listed for the 4HP22 and one for the 4HP22EH, as they could not tell me which of the three was needed for each specific hydraulic version of this transmission, for this write up, I got all of them. They were about AU$5.00 each. It took them 24 hours to deliver them to me via courier:-

Part # : Application
ZG-4005 : 4HP22
ZG-4025 : 4HP22
ZG-4105 : 4HP22
ZG-4205 : 4HP22EH

Photo below, the 4HP22EH gasket is in the lower left of the shot:

The Pan Gasket and Filter can be had from pretty much anywhere, all the local chain stores here in Australia such as Repco, Autobarn, Supercheap & Bursons carry them. The cheapest I found was a wholesaler by the name of Imparts.

Filter was AU$14.92 and the Pan Gasket AU$8.82. Part numbers are clearly shown in the photo below:

The Procedure:
The first step is to get the car in the air and get under it.  I used the combination of a trolley jack and 4 axle stands.

Once the car is in the air that should give you access to the bottom of the transmission.  Place one of the large plastic tubs under the transmission and undo the drain plug with a 5mm allen key.

Allow the transmission fluid to drain out.  It will take some time.  As you can see from the color of the fluid in my car, the previous owners had not followed any kind of maintenance schedule for some time.

Whilst you wait for the fluid to drain it might be a good idea to organise your work area.  I prepared a copy of the reference material to have handy during work.

Prepare you work area well, have plenty of space and a comfortable work position.  I also use a compartmentalised case as shown below to keep parts organised.

Once the fluid has finished draining remove the 6 bolts that hold the transmission pan onto the transmission.  Use a 10mm socket and ratchet with extension for this.  I find it easier to work from the back of the pan towards the front as it allows the last bit of fluid to drain out during pan removal.  You will need to either remove the filler tube from the pan, or disconnect the tube from the engine.  I found it easier to disconnect the tube from the engine using a 10mm socket.  It is a good idea to keep the plastic tub in place as ATF will continue to drip out of the transmission for several hours.

Inspection of the pan shows the kind of issues a lack of proper maintenance can cause.  The particulate matter does not provide a lot of hope for the condition of the clutches.

There are three bolts that hold the filter on. Remove these using your Torx 27 bit and the ratchet. When you remove the filter you can dump it in the bin.  Before you do, inspect the O-ring on the upper side of the filter, if it is in good condition you can reuse it.  If not you will need to source a replacement.  The photo below shows the O-ring in place, note there is more "gunk" inside the filter.

Moving back under the car it's time to disconnect the wiring.  Twist the ring around the end of the loom plug in an anticlockwise direction to disengage it.  Use a 30mm socket with a universal joint, 3" extension, and ratchet to remove the large nut around the socket.  Push the socket inside the transmission (direction of red arrow) using your fingers.

The valve body can now be removed from the transmission.  There are 13 bolts holding it in.  They have a slightly larger head than the rest of the bolts that hold the valve body itself together.  All the bolts are Torx 27.   I use a shoebox to keep track of which bolt comes from where.  They have different lengths and it's easy to loose track.  If you do, thats OK, but you will have more work later on figuring out which is which.

Here is more detail on the location of the bolts.  The orange arrows show the location of the 3 that hold the filter in place, the red show the remaining 13 that mate the valve body to the transmission proper.  When you do remove the valve body be careful not to damage the speed sensor at the rear, or the wiring harness and socket that will come out along with it.

Now we have the valve body out we can really get stuck into pulling it to pieces.  There are three sections on the top of the valve body that house the solenoids.  These sections need to be removed first.  The first one I removed was the MV5 solenoid body.  The green arrows show which bolts to undo to get it off.  All the valve body bolts are Torx 27.

6 bolts undone, don't forget to put them in their respective "shoebox" positions when you take them out.

With the bolts removed the MV5 solenoid body falls away.  Pay attention to the wiring harness and associated plugs they tend to be brittle after decades of bathing in hot ATF.  Carefully unclip the wiring as you go.

Next in line is the MV1 and MV2 Solenoid body, bolts shown below via blue arrows.

Once you have undone the six bolts, put a couple you have already removed (pink arrows) back in place to stop the lower front section of the valve body from moving around too much.

MV1 and MV2 solenoid body seperates easily once the 6 bolts are undone.

The last of the three upper solenoid bodies is the MV3 solenoid body.  This one requires only 3 bolts to be removed (yellow arrows).

Three bolts undone.  Once you get this one off the wiring harness will be free of the main bulk of the valve body.  Do not try to unplug the individual solenoid body sections from the harness.  The plugs will be too brittle.  At the same time try to avoid putting undue stress on the wiring.

MV3 solenoid body removed.

You can now remove the bolts you temporarily replaced to hold the lower front section of the valve body in place.  To remove it flip the valve body over while holding the lower front section in place with your hands.  Once you have it flipped over place it on the table and lift the main part of the valve body away from the lower front section.  Be careful when you do this, there are lots of small pieces inside the lower front section that may fall out if it is not correctly orientated when you seperate it from the rest of the valve body.

Once seperated from the lower front section place the rest of the valve body back on the table the way it was before you flipped it over. 

The red arrows show the parts you need to look out for.  On this version of the transmission we have 3 accumulator cups and 1 check ball.  Despite the care taken during seperation the check ball has still managed to migrate from the corect position (?).    Larger migrations may render components lost, and or jam the inner valves and springs.  Take care!   Use the magnetic screwdriver to remove the accumulator cups.

Remove the forementioned components and stick them to the relevant page of the ATSG reference.  Use sticky tape.  Take care not to mix them up.  Remove one compenent stick it onto the page in the correct position, double check it, and only then continue onto the next component.  Do not remove more than one at a time.

The lower rear section is next.  Green arrows highlight the 4 bolts to remove.

Use the same flip procedure to separate the lower rear.  Again be careful, more tiny things lurk within.  Red arrows show 2 accumulator cups, and a spring and plug combo.

Stick them down or loose them.  Due to their size I placed the spring and plug into the compartmentalised box shown above.

There are only 3 bolts left now, purple arrows.  These hold the main plate to the channel plate.

Once the bolts are out you can lift the main plate up off the channel plate.

The channel plate has 7 points of interest.  5 accumulator cups and 2 checkballs.

Once more, take them out one at a time, and tape them in one at a time.  Double check your work as you go.

One of the check balls in this particular channel plate is showing signs of severe wear.  Damage to this check ball can cause failure to engage reverse gear. 

A close up of the offending check ball shows it to be well worn and undersized.

A "large" divot has been taken out of it's centre.  A replacement is definately called for.

Removal of the solenoids themselves from their respective body is a matter of a spring clip held in by yet another Torx 27 bolt.  Removal facilitates cleaning with degreaser.

Retainer clips hold springs, shafts and valves in place.  Study the ATSG diagrams before removal.  Again, do not be shy with the degreaser.  Here is the MV1 and MV2 body in the process of disassembly.

Here is the lower front section with its front removed.  Lay the springs and other components out as the come out.  Pay attention and study the exploded diagrams found in the ATSG Reference.  Clean everything with a good bath in degreaser.

Be sure to clean the valve housing and cylinders.  Ensure they are free of any debris.  Put everything back together the way you found it.  Any broken or scored parts will need replacements.  Refer to the exploded diagrams and their associated legends for part identification.

Once the front of the lower front body is back together, tackle the rear of the same piece.

Try to keep everything orientated the same way when pulling parts out.

With so many components it's easy to loose track.   Study diagrams before you unbolt the section you are working on.  Be prepared!

Lower rear with front removed.

Lower rear with front and parts removed.  Note that the orientation of everything stays constant.  Use degreaser!  And then use some more!

Rear of the lower rear section.  Try to keep the bolts in place if you can.

Check those ATSG diagrams if you are unsure.  Better to be safe than autonomously and unexpectedly engaging reverse at 200kph on the Autobahn.

Before you put each section back together, make sure it looks nice and shiny, something like this MV5 solenoid body example.

When all sections have been completely cleaned up and reassembled put them in a safe place and take a break.

Removing the old gasket from the main plate can be one of the most frustrating jobs.  I use a razorblade and hobby knife.

Time consuming, but worth it.

Break out the multimeter and check the resistance across the solenoids and the speed sensor.  Don't worry too much if your speed sensor resistance reading is a bit out.  It's quite temperature dependant.  The correct values can be found in the ATSG reference.

7 pins, check the ATSG reference manual for numbering.

Cleaning the pan uses quite a bit of degreaser.

The replacement check ball as it arrived from ZF. AU$3.16 plus delivery.  ZF part number as per photo.

Prepare the channel plate with small dobs of vaseline.   Cut the components out of the sticky tape on the relevant ATSG page using the razor blade one at a time.   Replace the accumulator cups, pushing them into place through the vaseline with a pencil.  Check balls are easy enough to handle with your fingers.  Remember to double check each bit as you do it.   Make sure the cups are placed in the right direction, either up or down.

Repeat the procedure for the lower front section of the valve body.

And the lower rear section too.

Place the gasket and main plate over the top of the channel plate.  Ensure everything is aligned correctly.

Take the correct three bolts out of your "shoebox" and screw them hand tight into the main and channel plate assembly.

The vaseline should hold everything in place, so you can turn the lower front section upside down and place it onto the main plate.  Put two bolts in to hold it in place.  The top one in this photo can be hand tightened, the bottom one sits loosely as there is no thread to screw it into at this time.

Ensure the manual selector shaft is correctly orientated and sitting in the groove in the channel plate before you continue.

Fit the lower rear section, and hand tighten the four bolts indicated by the red arrows.

The three solenoid bodies can now be attached.  MV5 orange arrows.  MV1 and MV2 blue arrows.  MV3 green arrows.  Hand tighten all bolts.  Clip the wiring in place as you go.  The speed sensor can be positioned using its clip and two of the smaller torx 27 bolts.  Note that they can not be done up at this time.

The top side of the completed valve body.  Note the positioning of the speed sensor

Get back under the car and ensure that the mating surface on the bottom of the transmission is clean and free of debris.

Set your precision torque wrench to 8nm.  You do not want to overtighten any of the valve body bolts.  They can strip the thread from the valvebody easily, and uneven stresses across the valve body can lead to valves jamming.

Insert the wiring socket through the hole in the transmission and position the valve body.  Ensure the manual selector shaft is sitting on the pin of the cable assembly.   Also take note of the speed sensor.  Ensure it is correctly positioned inside its hole in the transmission.   Put the 13 bolts that mate the valve body into their respective positions and do them up hand tight.  Take your torque wrench and do up each bolt to the correct 8nm.  Work your way from the centre outwards in a spiraling pattern.

Put the 30mm nut onto the socket and do it up tight.  As when you took it off, use a 30mm socket, extension and universal joint with the ratchet.  Reconnect the cable, paying attention to the alignment of the 7 pins.  A quick twist on the ring in a clockwise direction should engage the snap lock.

Fit the O-ring to the upper side of the new filter.

Fit the filter with the last 3 Torx 27 bolts.  Remember, 8nm of torque!

Give your pan one last inspection for debris and then screw in the drain plug with a 5mm allen key.  Press the rubber pan gasket into place around the upper lip of the pan.

Refit the pan to the transmission.  6 bolts with 10mm socket.  Reconnect the filler tube to the engine with the 10mm hex screw.

Now you will need to fill up your transmission with anything upto 8 litres of Dexron III.  Use a funnel.  It's capacity is 9 litres for a dry fill.  You will find that you will have about a litre or so still in the torque converter. The transmission fluid temperature must be between 30-50 degree Celsius.  The vehicle must be without load and on even ground.  With engine running, switch the aircon on.  This will increase idle speed and ensure that oil passages in the transmission are filled with fluid.   Step on the brake firmly.  Apply parking brake fully. Move the selector lever through each gear position, pausing briefly in each gear.  Pull out transmission gear dipstick and clean with a lint free cloth. Reinsert dipstick completely. Pull out dipstick and place bottom tip on a level surface. Measure level from bottom tip.  Compare measurement and temperature with table below:

Once filled and measured as correct, replace the dipstick and cap.  Check for leaks.  If you have none, lower your car to the ground and head out for a well deserved test drive!

Job Done:
If you have questions or comments you should be able to track me down on www.bimmernut.com.  Until the next job.

Badsect0r