How To - 016 Quattro Transmission Axle Flange Seal R&R

["Fred Munro" <munrof@isys.ca>]

    This is one job guaranteed to come up on high mileage quattros - I just
replaced these seals today on my '91 200q, so I thought I'd put out a "how
to" while the experience is still fresh.
    WARNING - if these seals are leaking, you can lose over half of the
transmission oil without seeing any telltale driveway spots, so pay
attention to the oil level if you see seepage.

    1. Jack up & safely support the car. Remove the wheels.

    2. Break loose the filler plug. This takes a 17mm allen socket. This is
a steel plug in an aluminium case, so if there has been galvanic action, you
may have a challenge on your hands. If you can't get this plug out, you may
as well put everything back together, because you will have to add oil if
you pull the seals.

    3. Break loose the drain plug. Same situation as above. At this point,
decide whether you want to replace all the oil or just top it up. If you are
going to replace it (I'd recommend it at high mileage), drain the
transmission. Look for pretty little sparkly particles in the oil ( this, of
course, is a BAD SIGN).

    4. Index the CV joint and the axle flange. Remove the bolts which secure
the inner CV joint to the transmission axle flange. These take a 10mm triple
square socket. Don't even think about trying to use a Torx driver! On the
right side, you will have to remove the CV joint heat shield first. These
bolts are torqued to 59 ft.lb., so the axle will have to be secured to
loosen them. Putting the transmission in gear will work if the opposite
front wheel is on the ground - otherwise, you'll have to get creative.

    5. Seperate the CV joint from the axle flange and move it up and back to
get it out of the way. The axle can be wired to a handy little flange on the
leading edge of the wheel well to hold it in position. If you can't get the
CV joint clear, turn the front wheels to pull the axle outwards to get the
clearance you need.

    6. The axle flange is the inner seal for the CV joint, so it will be
full of black CV joint grease. Under the grease in the centre of the flange
is a 6mm allen head bolt which secures the flange to the differential
innards. Slide a drift through one of the flange bolt holes to engage a
transmission rib. Remove the 6mm allen head bolt.

    7. If you drained the tranny, pull out the flange. If you didn't drain
the tranny, put a drain pan under it and pull out the flange. If the oil
level is almost full, oil will run out. If you've lost most of your oil,
it's not an issue either way. Inspect the sealing surface of the flange for
wear.

    8. Clean the grit and old oil from the seal area. On the left seal, use
a depth guage to determine how far the seal is in from the outer housing
flange. Pop out the old seal with a large screwdriver.

    9. Install the new seal. The left side is a little tricky because there
is no flange to position the seal. If you are too enthusiastic with the
driver, you can drive the seal right into the tranny, which, of course, will
ruin your entire day. You can use a depth guage on the old seal to determine
how far to drive the new one in, or use an inspection mirror to position the
inner side of the seal on the inner edge of the seal housing. The right side
has a flange which the seal bottoms out on. If the axle flange sealing
surface is worn and you are too cheap to replace it, you may want to
position the seal a few mm out so it runs on a new surface.

    10. Fill the seal lips with multi-purpose grease and lube the sealing
surface of the axle flange. Slide the axle flange back into place. The 6mm
allen bolt is torqued to 10 Nm and then tightened another 90 degrees.

    11. Position the CV joint on the axle flange, aligning the index marks.
Torque the triplesquare bolts to 59 ft.lb. The factory coats the inside of
the bolt heads with soft green wax to protect the splines from corrosion. I
was plumb out of soft green wax, so I filled the heads with heavy chassis
grease. Install the heat shield on the right side.

    12. Fill the tranny with "liquid gold". The recommended lube is Audi G50
75W90 synthetic gear lube or equivalent. Do not use the Audi synthetic rear
diff lube by mistake - your tranny will not be happy. It is a darn good idea
to clean the drain and fill plugs and put antiseize compound on them in case
you ever have to do this again. Sometime around Jan. '88, Audi moved the
fill plug 15 mm higher on the tranny case. The later transmissions take 3.2
litres of oil, whereas the earlier ones take 2.2 litres. The tranny is full
when the oil is 7 mm below the fill hole, but it can be filled to the lower
edge of the hole.

    Put the rest of the car back together and motor on!


Fred Munro
'91 200q  260k km