This is a step by step DIY for four different transmission procedures. While this DIY was written specifically for an early production 6HP19, later 6HP19 and 6HP26 procedures should be very similar, if not identical. The four different procedures covered in this DIY are fluid replacement, fluid and transmission pan replacement, Mechatronic sealing sleeve replacement, and solenoid replacement.
If you are simply replacing fluid, the only part you will need is replacement fluid. I would also recommend replacing the drain and fill plugs, as both contain a rubber sealing ring, as well as the oil pan gasket if your pan has never been removed.
If you are replacing the Mechatronic sealing sleeve, you will need all of the aforementioned parts along with a new sealing sleeve.
If you are performing a routine fluid and filter replacement, you will need the service kit offered by the CTSC. The transmission filter has been integrated into the pan by ZF. The pan will come with a new oil pan gasket and drain plug pre-installed.
If you are replacing shift solenoids, you will need seven liters of fluid, shift solenoid kit, the four sealing sleeves (not to be confused with the 'Mechatronic sealing sleeve'), a new Mechatronic sealing sleeve, a new bridge seal, and a new foam solenoid insulator. If your pan/filter assembly has never been changed, you should also buy a new pan, along with a new fill plug.
Before we begin, I'll mention the mandatory disclaimer: By performing any repair to your car outlined in this thread, you assume ALL RESPONSIBILITY for any damage that occurs to you, your equipment, or your car. 100% on you, 0.0% on me. I also cannot guarantee this will solve your specific problems, if there are any present.
The only way to guarantee that would be to replace the entire transmission, which is exactly why BMW recommends it. However, these transmissions are repairable, and many transmission faults can be traced to failure in one or more components mentioned in this thread. Use your best judgement and carryout the repair YOU think is best for YOUR car.
This DIY also assumes you are comfortable performing somewhat complex repairs to your car, have access to all necessary tools, and are familiar with using INPA. You will need INPA to measure transmission temperature. If you don't have access to INPA, you will need to find some way to measure and monitor transmission fluid temperature.
Before we dig in I'll give you a little history on my car. I have a March of '04 build 530i, with ZF's 6HP19 automatic transmission. I bought the car with approximately 94,000 miles on it. Before I owned it, it was owned by a middle aged gentlemen who had the car serviced by BMW of Sarasota since new. So basically, my car was never 'abused' that I know of. I started experiencing some erratic shifting, along with error codes that would result in the transmission going into 'failsafe' mode. The codes I retrieved on a regular basis were 4F81 and 4F85, which reference slipping in the A clutch and E clutch of the transmission. After getting 4F85 five or six times, I knew that if I let it go too long I was going to be replacing the transmission, as slipping in the clutches will result in transmission failure. Since replacing the fluid and resetting adaptations didn't resolve the problem, I decided to dive in and replace the shift solenoids, as they are known to fail and cause the types of problems I was having. The shift solenoids are contained in the valve body, which ZF refers to as the 'Mechatronic'. I ordered all of my parts from thectsc.com. They are a great outfit to deal with, and I highly recommend them for any transmission parts needed for any of these procedures.
Before doing anything, you will need to have the car elevated on a lift or jack stands. You need to have it elevated enough to freely work completely underneath the car. If you use jack stands, please
be extremely careful. Safety first, everything else is second.
Let's get started...
: Remove center floor covering. The center floor covering is held my multiple fasteners of different sizes. Once all fasteners are removed, the covering will simply drop from the car without using any force.
: You will need to identify your transmission by finding the serial number plate. The plate should be on the outside of the casing, near the middle, and on the left side. This serial number is important if you are replacing solenoids and related seals, as they will need to be ordered by using this serial number. Below is a picture of the plate on my car, the number that is of importance is the one that follows the text "STUECKL". My transmission's number is '1071 010005', as you can see in the photo.
: Order the appropriate parts! I ordered all of mine from thectsc.com. If you need to drive the car for a few days without the floor coverings installed, be mindful of the fact that they are not there to protect your undercarriage. thectsc.com ships quickly, so you shouldn't be wating long. Once parts arrive, you are ready to proceed. Below is a picture of the parts I used for solenoid replacement, including the part number for the solenoid set that applies to my early build 6HP19.
: remove transmission FILL plug. I always remove the fill plug first, because I never want to find myself in a situation where I've drained all of the fluids out of a component with no way to get new fluids back in. Yes, it has been known to happen. I highly recommend removing the fill plug first. Below is picture showing the location of the fill plug (orange tube is inserted in this picture) relative to the drain plug. The fill plug is on the left side, towards the rear. an 8mm allen wrench works best to remove it.
: undo drain plug on transmission pan, drain transmission fluid into a clean drain pan. You will want to use a clean pan as the fluid should be recovered and set aside until all service is complete, as this drained fluid can be helpful if you run out of new fluid during any of these processes. While reusing old fluid is less than ideal, it is certainly better than running out completely. I used a plastic cat litter pan that held all of the drained fluid without running over. It was less that $6 and works great. Drain plug has been removed in this photo.
: Allow the transmission fluid to fully drain. If you are simply replacing the transmission fluid, reinstall the drain plug and skip to step 30.
: unbolt and remove the center exhaust system bracket. The bracket will need to be removed in order to fully access the transmission pan mounting screws at the rear of the pan.
: Remove all transmission pan retaining screws, then lower the transmission pan from the car. Be careful when lowering the pan, as there will still be a small amount of standing fluid in the pan. You can see from this photo why we need to remove the exhaust bracket. If you are performing a routine fluid and pan/filter replacement, skip to step 29.
: Unlock Mechatronic sealing sleeve by pulling down on unlocking lever. The sleeve is 'locked' into position by this lever. Unlocking the lever should NOT take much force at all. I was able to unlock it by gently pulling down with two fingers.
: disconnect wiring harness connector at the Mechatronic sleeve. If you look at the connector, you will see a square tab at about the 5 o'clock position. I used a 1" wooden dowel to undo the connector. Place either a finger, dowel, or any other appropriate tool on the tab. The connector will unscrew by rotating it in a COUNTER-CLOCKWISE motion. Once the connector is fully unseated, push it up and out of the way to fully expose the Mechatronic sealing sleeve.
: remove Mechatronic sealing sleeve. The mechatronic sleeve can be removed by gently rocking the sleeve from side to side while pulling it outward, either by hand or with a set of pliers. There is only a very small amount of room between the transmission and the transmission bracket, so unless you have really small hands a set of pliers similar to what I used is probably going to be the best route. These are the pliers I used, as they allowed me to get good clamping force on the sleeve while extracting it. DO NOT attempt to remove the sleeve with a twisting motion, as you risk cracking the locating tab that is molded into the Mechatronic connection point. Here you can see the sleeve relative to the locking lever, as well as the limited amount of work area you'll be dealing with. If you are only replacing the Mechatronic sealing sleeve located on the outside of the transmission, skip to step 26.
: unbolt Mechatronic mounting bolts. It is very important to support the Mechatronic while you are unbolting it from the transmission. If you don't have it supported, it WILL fall on the ground, likely break, and put a $1700 dent in your wallet. It is also vital that any time you are handling the Mechatronic you do NOT allow anything to come into contact with the pins in the electrical connector. Any static electricity that is discharged into the pins will likely destroy the TCM and require replacement. Take your time and be careful!! Below are two diagrams showing the bolt pattern for the Mechatronic. Compare the stampings in yours, and remove the appropriate bolts while supporting the Mechatronic.
: Carefully lower Mechatronic from transmission, and place on a clean working surface. I used a workbench with two blocks of 2x4 to support the Mechatronic while I worked with it.
: remove mounting bolts securing TCM to the Mechatronic. The TCM is the computer portion of the Mechatronic, encased in black plastic. The bolts that hold the TCM to the Mechatronic are the same size as the ones that hold the two aluminum halves of the Mechatronic together. It is very important to only remove the bolts that are holding the TCM in place. By turning the mechatronic over and following the bolts from one side to the other, it should become apparent which bolts are for the TCM.
: carefully lift TCM from Mechatronic. The TCM uses two metal pins that act as guides. The TCM should lift from the Mechatronic with a minimal amount of force; some gentle rocking and lifting upwards will allow it to separate. If you are unable to get it to budge, you likely have one or more bolts still holding it in place. After separating the TCM from the Mechatronic, store in a safe location. Your Mechatronic should now look like this:
Guide pins for the TCM:
: unbolt the shift solenoid retainer plate.
: Once the retainer bolt is removed, the solenoids are ready to come out and be replaced. The solenoids can be removed by hand by pulling outward and gently twisting at the same time. I replaced mine one at a time, matching colors of the old to new as I worked my way down the line. If for some reason you see green solenoids, the replacements are blue. Match yellow to yellow, and black to black, noting the position the of solenoids before removing.
: press replacement solenoids into Mechatronic by hand, ensuring that the terminals are facing in the same direction as the old solenoids that were removed. Ensure that you have the solenoids fully seated in the Mechatronic, as shown below.
: carefully lower TCM onto Mechatronic, press gently into mounting position, then remove. This will help line up all of the terminals on the solenoids to their correct mounting positions. Unless you are a robot, your solenoids will likely look like mine after you install them by hand. If the terminals are not lined up perfectly, the TCM will not fully seat against the valve body. 'Dry fitting' the TCM will aid in lining everything up.
: After all of the solenoids are lined up, it's time to install the solenoid retainer plate. The retainer plate is there to fully lock the solenoids into position. Torque spec for the retainer plate bolts is 5 ft/lbs. The retainer plate can only be installed in one position; if it won't seat flat against the valve body, flip it around.
: turn the TCM upside down, you should see the foam insulating strip. Remove and replace. (Sorry, forgot to take a picture of this)
: install TCM back onto Mechatronic by lining up the guide pins and gently pressing the TCM flat against the aluminum portion of the valve body. Torque spec for the TCM mounting bolts is 5 ft/lbs. You have just finished solenoid replacement, and the Mechatronic is now ready to be installed back into the transmission. Before we can install it, we need to replace the four sealing sleeves and the somewhat infamous bridge seal or 'adapter seal'
In this photo, you can clearly see the four sealing sleeves to the right, and the bridge seal to the left. These seals are a known failure point, and can cause a host of issues.