Wrenching in the Bay Area - 020 tranny flange swap compatibility

[amalventano@sc.rr.com (Allyn)]

> and it test fit just fine.

please allow me to demonstrate:

ref: http://scirocco.dhs.org/vw/pics/flange-1.jpg
this pic shows a 100mm flange on the left, and a 90mm flange on the right.
to the left of the 100mm flange is the 100mm style seal carrier and a seal
beside it. all items are arranged in-line, as to their relative
(cross-sectional) position when installed on the tranny. you can see how the
green sleeve is designed to go from the 90mm style seal location to the
100mm style location. this is mainly for fyi to all listers and is not
really showing much yet. i would have a 90mm seal next to the 90mm flange,
but i destroyed them during removal.

later in this post i mention 'inner' and 'outer' parts of flanges. 'inner'
would be towards the top of this pic, as it points into the tranny when
installed.

ref: http://scirocco.dhs.org/vw/pics/flange-2.jpg
this is the seal surface of the 90mm flange

ref: http://scirocco.dhs.org/vw/pics/flange-3.jpg
this is the 100mm flange. the bottom machined surface is the seal surface.
the surface that appears to be the same as the 90mm surface is actually
intended to hold the lsd preload spring. the spring is held in at the widest
part of the taper, where it levels off, which is at the bottom of the
narrower section, right before you hit the wider seal surface.

ref: http://scirocco.dhs.org/vw/pics/flange-4.jpg
here it becomes more obvious. the 90mm flange is on the right. its surface
is completely flat, where the 100mm flange is tapered. at the outer portion
of what would have to be inserted into the 90mm seal, the 100mm flange is
much wider than the 90mm flange. this means you basically have to hammer the
100mm flange down into the 90mm seal, as it would be such a tight fit (on
the outer part of the seal). it is important to note that the outer part of
teh seal is not the actual sealing surface. the sealing surface (flexible
part of the seal) is the inner part. this is indicated by the oil colored
band near the end of the 90mm flange. this same location on the 100mm flange
is narrower, so it simply wont seal properly.

ref: http://scirocco.dhs.org/vw/pics/flange-5.jpg
shot poorly trying to show that the 100mm flange extends out further than
the 90mm flange. this is better shown in shot 1.

now enough of the seal stuff, here is the machining that tobias may have to
do:

ref: http://scirocco.dhs.org/vw/pics/flange-6.jpg
this is the patch you must grind. it must be this long since the flange edge
must clear the tranny housing as the flange is slid on. you cant just grind
the one spot where it would sit, as the flange cant be installed at an
angle. note the green seal carrier installed.

ref: http://scirocco.dhs.org/vw/pics/flange-7.jpg
flange installed.

ref: http://scirocco.dhs.org/vw/pics/flange-8.jpg
tranny 100mm flange swap completed, with carriers on both sides. oil puddle
on ground is due to me forgetting that these trannies have breathers :).

phew!
hth
Al