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Audi A4 Transmission Removal
 
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Pelican Technical Article:

Audi A4 Transmission Removal

Peter Bodensteiner

Time:

8 hours8 hrs

Tab:

$0

Talent:

****

Tools:

Jack and jack stands, sockets and ratchet handle, straight and swivel extensions, offset 16mm wrench, Allen wrenches and sockets, 8mm internal (male) 12-point socket, torque wrench, flathead screwdriver, penetrating lubricant

Applicable Models:

Audi A4 (1997-01)
Audi A4 Quattro (1997-01)

Parts Required:

Drive axle gaskets

Hot Tip:

Disconnect the ground on battery before starting. Unless you've done this before, set aside a weekend and don't count on driving your car to work on Monday morning because you will probably hit a snag or two.

Performance Gain:

Removing the transmission allows for transmission repairs and clutch replacement or upgrade

Complementary Modification:

Transmission mount replacement

There are really only a couple of reasons why you would remove your transmission. The most obvious is that you need to replace or repair the transmission itself. The most common reason, though, would be to replace the car's clutch--a critical but (fortunately) somewhat infrequently required wear item for any manual-transmission car.

This project will walk you through all of the steps you need to take to remove the transmission from a quattro-equipped A4. A front-wheel drive car would be broadly similar, except that there is no rearward-facing driveshaft to remove, only the two front axles. Because of the length of the project, we have broken out the actual procedure for replacing the clutch and clutch release bearing, as well as the removal of the transmission mounts into separate projects.

A word of advice--set aside a full weekend for removing and replacing your transmission. Beyond that, at the very least make sure you have lined up an alternative way to get to work on Monday morning. You're probably going to hit a snag or two, and you don't need to add the stress of losing your sole means of transportation to add to your frustration.

First you will need to jack up the car, disconnect the battery, remove the plastic under tray, remove the air filter housing, move the coolant expansion tank aside and remove the forward oxygen sensor. Please see our article on these projects for additional assistance and before starting this project

Later on, you will need the to remove the right-side transmission mount, forward sensor, , the catalytic converter and down pipe. I will point those items out as we reach them during the sequence below.

A short primer on the engine-to-transmission bolts. There are 10 bolts, all with 16mm heads, but they have different lengths. All but one of them thread directly into the engine block--the exception (Bolt 8) has a nut on the back side. I have used the Bentley manual's numbering of these bolts for consistency should you be using that manual for reference also. Bolts 1 and 2 actually secure the starter motor in place against the transmission. See our starter replacement article for more information on these two bolts. Note that the wires connected to the starter do not need to be removed here. When removing the bolts, leave Bolt 10 and Bolt 6 for last. When you are putting the transmission back on, tighten all the bolts to 48 ft-lbs. except for bolts 7 through 10, which should be tightened to 33 ft-lbs.

This thin metal bracket attaches to the back side of the front sub frame with two 10mm bolts.
Figure 1

This thin metal bracket attaches to the back side of the front sub frame with two 10mm bolts. The bracket itself provides three mounting spots for the front plastic under tray. Remove the bracket and tape the two bolts to it for safekeeping

Now, the Bentley manual says you need to remove this engine speed sensor from the transmission as part of the transmission removal procedure.
Figure 2

Now, the Bentley manual says you need to remove this engine speed sensor from the transmission as part of the transmission removal procedure. However, the sensor is actually inserted into the engine block, not the transmission, so I'm not sure how necessary this step is. There are some holes in the transmission that are roughly the correct size to fit this sensor, so perhaps this was a running change by Audi.

Nevertheless, you'll need a 5mm Allen-head socket or wrench to remove the hold-down bolt that secures the sensor.
Figure 3

Nevertheless, you'll need a 5mm Allen-head socket or wrench to remove the hold-down bolt that secures the sensor. It is located in the engine block just behind the oil filter, which explains why there is so much accumulated dirt and grime in this location. The red circle indicates the end very of bolt number 6 of the 10 engine-transmission bolts (the head of the bolt is to the rear of the car) that need to be removed to separate the two components.

This photo should orient you to the left side of the transmission.
Figure 4

This photo should orient you to the left side of the transmission. The axle is attached to the transmission by six 12-point bolts (the right-side axle is just the same, except that the axle is shrouded by a heat shield just above it). The blue arrow points to the transmission mount. The two red arrows point to two sensor connectors that need to be detached from the transmission in order to remove it.

Here's a closer view of those two electrical connectors.
Figure 5

Here's a closer view of those two electrical connectors. Note bolt 6 on the left side of the photo (the other side of the same bolt that is seen in the red circle in Picture 3. The blue arrow points to the clutch slave cylinder bracket and the bolt that must be taken out to remove the slave cylinder from the transmission. There's more detail on this procedure in the clutch slave cylinder article.

In this photo, taken from below the axle with the camera pointed straight up, the connector closest to the axle has been disconnected.
Figure 6

In this photo, taken from below the axle with the camera pointed straight up, the connector closest to the axle has been disconnected.

For both of these connectors, use a flathead screwdriver to release the metal clip from the connector, and then simply pull the two halves of each connector straight apart.
Figure 7

For both of these connectors, use a flathead screwdriver to release the metal clip from the connector, and then simply pull the two halves of each connector straight apart.

Let's get at those axles.
Figure 8

Let's get at those axles. This is the special tool you'll need to remove the six bolts that attach each axle to the transmission: an 8mm, 12-point socket.

With the wheel removed, you can reach the axle bolts from the wheelwell with the socket, a long extension or two, and your ratchet.
Figure 9

With the wheel removed, you can reach the axle bolts from the wheelwell with the socket, a long extension or two, and your ratchet. Be sure that your socket is seated well within the each axle bolt to avoid stripping the bolt.

Remove each axle bolt one at a time.
Figure 10

Remove each axle bolt one at a time.

The axle bolts are paired up using these semicircular collars.
Figure 11

The axle bolts are paired up using these semicircular collars.

Once you remove all the axle bolts, you may find you can only move the axle about this far away from the transmission mounting flange.
Figure 12

Once you remove all the axle bolts, you may find you can only move the axle about this far away from the transmission mounting flange. However, the end of the axle is flexible and can be pivoted to provide more clearance.

Once the axle is away from the mounting flange, you can rest it on the suspension links and/or sub frame of the car.
Figure 13

Once the axle is away from the mounting flange, you can rest it on the suspension links and/or sub frame of the car. You may want to cover the end of the axle with a plastic bag or something similar to help prevent the sticky axle grease from getting onto your hands or arms.

On the right side of the transmission, remove the axles the same way as you did on the left side.
Figure 14

On the right side of the transmission, remove the axles the same way as you did on the left side. You can remove the heat shield above the axle first, or you can remove the axle first. As you can see here, access to the heat shield bolts is greatly improved by moving the exhaust out of the way see the turbo replacement article and the transmission mount article for more information.

Use an 8mm Allen-head wrench or socket to remove the three axle heat shield bolts.
Figure 15

Use an 8mm Allen-head wrench or socket to remove the three axle heat shield bolts. The red arrow points to a thin rubber gasket that you'll find inside the axle joint once you open it up. Make sure to replace these gaskets when you reattach the axles.

The shifter inside the car connects to the transmission via two rods.
Figure 16

The shifter inside the car connects to the transmission via two rods. The rods connect to the transmission as shown. This photo is taken from underneath, looking up at the right side of the transmission.

The rod with the black rubber bushing is called the shift rod, while the other one is called the pivot rod.
Figure 17

The rod with the black rubber bushing is called the shift rod, while the other one is called the pivot rod. The shift rod connects to a metal bar that extends rearward out of the transmission with a small bolt with a 10mm head. This bolt does not thread into or through the transmission's metal bar--it merely acts as a set screw that rests in a detent in the metal bar to hold it in place.

Once the shift rod is removed, you can see the bar to which it was attached.
Figure 18

Once the shift rod is removed, you can see the bar to which it was attached.

Use an 8mm Allen-head wrench to remove the bolt in the end of the pivot rod.
Figure 19

Use an 8mm Allen-head wrench to remove the bolt in the end of the pivot rod.

I could only remove the bolt a little bit before I no longer had room for the Allen wrench.
Figure 20

I could only remove the bolt a little bit before I no longer had room for the Allen wrench. So, I removed it this far and then, when the transmission was lowered a little bit, I had better access and could remove the entire bolt.

This simple bar connects to the two sub frame mounting points.
Figure 21

This simple bar connects to the two sub frame mounting points. It needs to be removed to lower the transmission out of the car.

Remove the 16mm bolts at both ends of the bar and remove it.
Figure 22

Remove the 16mm bolts at both ends of the bar and remove it.

The next step is to detach the driveshaft from the end of the transmission, at least on quattro-equipped cars (actually, it is the end of the Torsen differential cover, but that's just being technical).
Figure 23

The next step is to detach the driveshaft from the end of the transmission, at least on quattro-equipped cars (actually, it is the end of the Torsen differential cover, but that's just being technical). Similar to the front axles, the driveshaft is held on with six bolts with metal collars pairing up the bolts into three sets of two. In this case, though the bolts are 6mm Allen-head bolts. The Bentley manual indicates that there is a heat shield protecting this joint that must be removed, but I found none on my 2000 model year car. It did have a rubber piece there, but it didn't need to be removed.

Use your 6mm Allen socket or wrench and remove the six driveshaft bolts.
Figure 24

Use your 6mm Allen socket or wrench and remove the six driveshaft bolts.

After removing the driveshaft bolts, I had some trouble getting the driveshaft and transmission to actually part ways.
Figure 25

After removing the driveshaft bolts, I had some trouble getting the driveshaft and transmission to actually part ways. After much consternation and confusion, I discovered that I really just needed to hit it with a bigger hammer. I duct-taped two regular hammers together and whacked the end of the driveshaft and the joint separated just fine.

Here's a better look at the end of the transmission.
Figure 26

Here's a better look at the end of the transmission.

Now you should be ready to start removing the engine-to-transmission bolts.
Figure 27

Now you should be ready to start removing the engine-to-transmission bolts. Bolt 3 secures this flat metal bracket. The bracket secures two wires that wrap around from the rear of the engine and weave their way down to the front of the starter motor. As mentioned in the main text, Bolts 1 and 2 secure the starter motor to the transmission and have already been removed.

Bolt 4 is dead-center at the top of the transmission and is buried underneath so many wires and hoses that it's impossible to photograph.
Figure 28

Bolt 4 is dead-center at the top of the transmission and is buried underneath so many wires and hoses that it's impossible to photograph. In this photo I have my fingertips touching Bolt 4 so you have some idea of where it is. Keep its central location in mind and you will find it. Get a long ratchet and socket on it and you will be able to loosen it. After a few turns you may be able to remove it by hand.

Bolt 5 is similarly hard to reach, but at least I could get this photograph of it (red arrow).
Figure 29

Bolt 5 is similarly hard to reach, but at least I could get this photograph of it (red arrow).

This is Bolt 5 once it has been removed.
Figure 30

This is Bolt 5 once it has been removed. Note its length--Bolts 5 and 11 are 110mm long; Bolts 1, 3 and 4 are 67mm long, Bolts 2 and 6 are 90mm long, and Bolts 7 through 10 are 45mm long. Make sure to have these lengths straight when you replace the transmission.

Working our way around the transmission now, remember that we will skip Bolt 6 (red arrow), as it should be one of the last two to be removed.
Figure 31

Working our way around the transmission now, remember that we will skip Bolt 6 (red arrow), as it should be one of the last two to be removed.

Bolt 7 has a 16mm head on the front and a nut on the back, which you can secure with an 8mm Allen wrench in order to loosen.
Figure 32

Bolt 7 has a 16mm head on the front and a nut on the back, which you can secure with an 8mm Allen wrench in order to loosen.

After removing Bolt 7 (now with a blue number), move on to Bolt 8.
Figure 33

After removing Bolt 7 (now with a blue number), move on to Bolt 8. This is where the offset wrench comes in handy, as the clearance between the transmission and the sub frame is quite tight.

It is possible to remove these bolts even given the tight quarters.
Figure 34

It is possible to remove these bolts even given the tight quarters. However, I discovered a very handy tip when it came time to replace these bolts at the end of the job. At that point I found it was necessary to lift up the engine a couple inches to gain some more clearance. It sounds daunting, but it's really not, and I realized that it would have made the removal of these bolts much easier as well. Refer to the engine mount article for more information, but really it's as simple as zipping off two easily accessible 13mm nuts from the bottom of the engine mounts and lifting the engine a little bit with a floor jack. If you choose to do this, put the engine back in place and replace the nuts after you remove these two bolts--you'll want the engine back in its normal position for the removal and replacement of the transmission. Then, when you need to replace Bolts 8 and 9, you can lift the engine again, temporarily, and you'll have plenty of room to put the bolts back.

Again, note the tight clearance for Bolt 9.
Figure 35

Again, note the tight clearance for Bolt 9. Looking ahead, Bolt 10 threads in from the front like Bolts 8 and 9, while Bolts 11 (and Bolts 1 and 2 for that matter) thread in from the rear.

There's Bolt 9 out of the way.
Figure 36

There's Bolt 9 out of the way.

Looking from below, we're working on Bolt 11, which is one of the two bolts, along with Bolt 6, that pass through dowel sleeves that help locate the transmission bell housing to the engine block.
Figure 37

Looking from below, we're working on Bolt 11, which is one of the two bolts, along with Bolt 6, that pass through dowel sleeves that help locate the transmission bell housing to the engine block. You also get a good look at the lower of the two starter motor bolt holes.

Note that you'd need to have removed the right-side axle in order to remove Bolt 11, which is one of the longer transmission bolts, at 110mm bolts.
Figure 38

Note that you'd need to have removed the right-side axle in order to remove Bolt 11, which is one of the longer transmission bolts, at 110mm bolts. In a bit of a continuity error caused by shooting things out of sequence, you can see that I have yet to remove the axle here.

Get your floor jack ready and place it under the lowest point of the transmission, which is below the drive axles.
Figure 39

Get your floor jack ready and place it under the lowest point of the transmission, which is below the drive axles. Make sure the wheels of the jack are placed where they will have several inches to roll freely toward the back of the car. Most of the mass of the transmission is at the front, so while you may need a big of support at the rear, you should support it like this, near the front.

Lift the jack so that it takes the full weight of the transmission and then stop lifting.
Figure 40

Lift the jack so that it takes the full weight of the transmission and then stop lifting. Now you need to keep the transmission level and move it straight to the rear until the input shaft clears the fingers of the clutch pressure plate. Here you can see that the transmission has begun to separate from the engine block (red arrows), but it still needs to be moved back a few more inches.

This should do it.
Figure 41

This should do it. Don't lower the transmission all the way quite yet, though. Instead, ease it down until you can reach the clutch slave cylinder assembly and remove it from the bell housing see the clutch slave cylinder article, and until you can remove the Allen-head bolt from the shift pivot rod (see Picture 20). Note the numbers and arrows that show where various bolts were once fastened.

Once the transmission is free of all its attachments, you can lower it the rest of the way and move it as far back as necessary to access the clutch.
Figure 42

Once the transmission is free of all its attachments, you can lower it the rest of the way and move it as far back as necessary to access the clutch. The transmission has rocked a bit over to the left side of the car--remember that Bolt 4 is right at the top. Despite all that you've been through to get to this point, the hardest job remains--putting the transmission back in place. It's not really anything that a photo will help you with, but I have a few recommendations. First, have at least one friend help you position the transmission. Remember to reattach the shift rod and the clutch slave cylinder after you've raised the transmission a bit, but before you it all the way up. Keep the faces of the transmission and engine block parallel as you bring them together, and move carefully to ensure the transmission input shaft doesn't catch on the clutch pressure plate fingers. Last, you're not going to be able to push the transmission all the way against the engine block by hand, but you will get it close enough that you can start to put bolts in and pull the transmission in to the engine. Don't thread any of the bolts in all the way at first--tighten them in increments and work your way around the circumference of the transmission. Throughout this whole process, work slowly, make small adjustments, and maintain your patience. Keep those faces parallel and eventually you will reunite the two.











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