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Repair Summary
This article gives detailed instructions on servicing the transmission in a BMW E46 3 series vehicle. Even though we used a 2004 325ci to perform this repair, this article can be applied to any 1998-2006 3 series vehicle with minor modifications to the repair steps.
See all vehicles this article applies to
E46 3 Series 325ti
E46 3 Series 318td
E46 3 Series 320td
E46 3 Series 318ti
E46 3 Series 330xi
E46 3 Series 330i
E46 3 Series 330xd
E46 3 Series 330d
E46 3 Series 316ti
E46 3 Series 328i
E46 3 Series 325xi
E46 3 Series 325i
E46 3 Series 320i
E46 3 Series 323i
E46 3 Series 320d
E46 3 Series 318i
E46 3 Series 318d
E46 3 Series 316i
E46 3 Series M3 CSL
E46 3 Series M3
E46 3 Series 330Ci
E46 3 Series 330Cd
E46 3 Series 325Ci
E46 3 Series 323Ci
E46 3 Series 320Ci
E46 3 Series 320Cd
E46 3 Series 318Ci
E46 3 Series 328Ci
E46 3 Series 316Ci
E46 3 Series 323i 2.4
E46 3 Series 316i 1.9
E46 3 Series 316i 1.6
A BMW E46 transmission service is inexpensive insurance against early failure of your vehicle's drivetrain.
So...did you hear that rumor floating around that all 3 series cars built between 1998 and 2006 (E46) have "lifetime" fluid fills in their automatic transmissions and they never need to be serviced?
Hmmmm. Well it's not a rumor. In fact BMW was kind enough to scare the bejesus out of us by plastering a green WARNING sticker on the bottom of every E46 tranny verifying this. But what exactly is their definition of "lifetime"? Is it the lifetime of the owner (yikes)? The lifetime of the car (not sure what defines that)? Or is it the lifetime of the transmission before it burns up and leaves you stranded from not being serviced?
The term "lifetime" actually means the "service life" of the transmission, which in the case of the BMW E46 is 100,000 miles. In other words, BMW recommends that the transmission fluid does not need to be changed or topped off until after the vehicle surpasses 100,000 miles. This is simply a recommendation and not the law. Like every other mechanical part on your vehicle, the transmission needs to be regularly serviced to keep it operating correctly. Period...end of story.
The BMW Repair Guide recommends at a minimum an E46 transmission service fluid and filter change every 60,000 miles. This recommendation is for "normal" driving conditions. If you track/race your vehicle or are a more aggressive driver, we suggest a BMW E46 transmission service even more frequently.
Table A - E46 Automatic Transmission Guide
| Model | Year | Transmission |
| 323i/Ci/iT | 1999-2000 | A5S360R (GM) (up to 03/00) A5S325Z (ZF) (from 03/00) |
| 325i (M54 engine) | 2001-2005 | A5S325Z (ZF) (up to 03/02) A5S390R (GM) (from 03/02) |
| 325i (M56 engine) | 2003-2005 | A5S325Z (ZF) |
| 325Ci | 2001-2005 | A5S325Z (ZF) (up to 03/03) A5S390R (GM) (from 03/03) |
| 328i/Ci | 1999-2000 | A5S360R (GM) (up to 05/00) |
| 330i/Ci/Cic | 2001-2005 | A5S325Z (ZF) (up to 03/03) A5S390R (GM) (from 03/03) |
| 325xi/xiT 330xi/xiT | 2001-2005 | A5S390R (GM) |
| 325iT | 2001-2005 | A5S390R (GM) (up to 03/03) A5S325Z (ZF) (from 03/03) |
View the detailed parts diagram for this repair.
Includes detailed part diagrams, part numbers and links to purchase all of the required components needed to complete this repair.
Section 1 - Draining and removing the transmission oil pan
- Jack and support both ends of your vehicle. Please click here to learn how to properly jack and support your vehicle for this repair.
- Locate the transmission oil pan. It is located behind the engine underneath the vehicle.
- BMW used three different transmissions in the E46 3 series (see Table A above to identify yours). It is very important to verify your part numbers and the bolt count and pattern on your transmission gasket before beginning this repair. We can’t tell you how frustrating it is to be sent the wrong gasket, only to find out after we have drained and removed the transmission oil pan. Save time and stress and double check before you start the repair.
- Before draining the oil pan, always remove the fill plug first. You do not want to find out after the transmission is serviced that the fill plug is stuck and fluid can't be added.
- Start by lLocating the transmission fill plug on rear left side of transmission. You will notice that there is very little clearance between the plug and the frame of the vehicle - it is impossible to get a regular length 8mm hex socket and wrench in the fill plug. The solution is to simply cut an inexpensive 3/8" drive 8mm hex socket down with a Dremel tool as shown below. This will give you a custom low profile 8mm hex socket that will work with both a regular 3/8" drive socket and torque wrench. ***Do not use a 1/2" drive hex socket...it will be too large even after modifying it.
- Using the modified 8mm hex socket, remove the fill plug from the top of the transmission. You will most likely need a breaker bar to initially loosen the plug.
- You can now drain the transmission. Position a 5 gallon drain pan under the transmission drain plug, located at front of transmission oil pan.
- Use a T40 torx bit to remove the transmission drain plug. Let oil thoroughly drain from pan. The transmission drain plug is notorious for stripping when attempting to remove. Some model transmissions (most notably the A5S325Z) have a high torque value on their drain plugs, making them nearly impossible to remove without stripping the torx head. If your transmission drain plug strips while trying to remove, go to the next step 9. If not, proceed to step 10.
- If you strip the torx drain plug while trying to remove, you will have to drill and extract it out. Don’t feel bad, we stripped ours too while making this article. Use a 5/16” titanium drill bit to drill through the center of the plug into the pan. Make sure to have your drain pan ready...as soon as you drill through the plug the pan will start draining.
- Spray the transmission oil pan bolts down with PB Blaster and allow to soak for about 10 minutes.
- Use a T27 torx bit to remove the oil pan bolts. The oil pan bolt heads have a tendency to strip on the BMW E46 transmission. Iif you strip one, don’t get frustrated...just move on. The stripped bolt heads can be very easily snapped off with a drill. If you strip a torx bolt during removal, proceed to step 12 for instructions on removing it. If you were able to get all of the oil pan bolt out successfully, proceed to step 13.
- If you strip an oil pan mounting bolt (which is a normal occurrence), use a ¼” drill bit to quickly remove its head. Simply start drilling into the center of the bolt as shown below and the head will quickly twist off. You can easily extract the rest of the bolt with your fingers after the pan is removed.
- Remove the oil pan from the bottom of the transmission. Remove the old gasket.
- Use a T40 torx bit to remove the two bolts (front and back) anchoring the transmission oil filter. Remove the filter from the transmission.
Section 2 - Reinstalling the oil pan and gasket
- Thoroughly clean the oil pan inside and out. Using CRC Brakleen, liberally soak the inside and outside of the pan and scrub with a rag. Remove the magnets and clean them thoroughly as well. The pan should look “new” inside when you are finished. The goal is to remove every bit of metal shavings and residue left inside the pan so it does not recirculate with the fresh fluid we will be adding.
- If you had to drill out the torx drain plug in section 1, you will now need to extract the old one out of the pan (if you didn’t proceed to next step). Soak the plug inside and out with PB Blaster and let sit for 5 to 10 minutes. Next, hammer a bolt extractor into the hole that was drilled into the plug and turn with an open ended wrench to extract.
- Install the new transmission oil filter following the reverse steps above. Make sure your filter has a rubber gasket ring on it as shown below. Torque the two filter mounting bolts to 9 Nm (6.5 ft-lb).
- Using a high quality RTV silicone gasket sealant, squeeze out six small spots around the perimeter of the oil pan as shown below. These are to help hold the new gasket in place during installation. Lay the new gasket on top of the spots of sealant and let dry for about 10-15 minutes. Put the magnets back in the pan.
- Reinstall the oil pan on the bottom of the transmission using new oil pan bolts. Don't forget to put the magnets back in the pan. Torque the pan bolts in sequential order (you do not need to use a cross pattern). Use one of the following tightening torques on the pan bolts, depending on your transmission model number (check your model number in table A at beginning of this article): A5S360R / A5S390R (GM Transmission) - 10Nm (7 ft-lb) A5S325Z (ZF Transmission) - 6 Nm (4 ft-lb)
- Install a new drain plug in the pan and torque to one of the following values: A5S360R / A5S390R (GM Transmission) - 20Nm (15 ft-lb) A5S325Z (ZF Transmission) - 35 Nm (26 ft-lb)
Section 3 - Refilling the transmission with fluid
Refilling the BMW E46 five speed transmission is a two step process. First the transmission oil pan must be initially filled. After the initial fill, the transmission must be warmed up to its final fill temperature (100F) before topping off with fluid. Per the manufacturer specifications, the vehicle must be running and the transmission in park while topping off the transmission - topping of the transmission with the engine off could cause an under filled transmission. - Fill your fluid transfer pump with 6 quarts of approved transmission fluid. Pump the oil pan completely full of transmission fluid until it begins to pour back out through the fill hole.
- Install the new fill plug hand tight. DO NOT torque it yet. You will need to remove it to top off the fluid after bringing it to the final fill temperature (100F).
- Start the car to warm up the transmission. Using a BMW diagnostic scanner, hook up to the OBDII port and get to the correct screen that displays the gear box temperature.
- With your foot on the brake, slowly shift through the gears, pausing 3 seconds between gear changes. Repeat this process about six times. This will circulate the transmission fluid through the valve body and other transmission components.
- When the transmission reaches 100F, leave the vehicle running and in park and proceed directly back to the transmission fill hole.
- Remove the fill plug and finish pumping fluid into the transmission until it starts to flow out of the hole. Your transmission is now properly filled.
- Replace the new fill plug and torque to one of the following values:
- A5S360R / A5S390R - 20Nm (15 ft-lb) A5S325Z - 30 Nm (22 ft-lb)
- With the engine still running, check for any visual leaks around the gasket.
- You can now turn the engine off.
BMW E46 Transmission Service Finished
