Wrenching in the Bay Area - 020 tranny flange swap compatibility

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

tobias,
> (includes taking flanges off the old tranny and attaching to the
> new

going to 100mm? be prepared to use a die-grinder on the housing for
clearance issues. i just did this exact thing during the engine swap on the
rieger. also realize you will need two (yes, two) green seal carriers for
the tranny that used to have 90mm flanges, along with new 100mm type seals
to go into the green carriers. on trannies that come with 100mm flanges, one
half of the housing was revised to accept the 100mm seal directly, but the
other half remained the 90mm style, hence the green carrier. another
important note: dont plan on using the old carriers from the old tranny, big
gamble trying to get those out without bending/deforming them.

some people *think* the 100mm flange will 'plug into' the 90mm type seal, as
the 100mm flange has a second machined surface which appears to be the same
size as the one on the 90mm flange. what they dont realize is that the
second surface is beveled on the 100mm flange, and is flat on the 90mm
flange. forcing a 100mm flange into the 90mm seal will not leak initially
(due to extremely tight fit), but due to the bevel it rides on the outer
part of the seal (the part that wasnt intended to seal - the inner lip is
the actual fluid seal). once the outer wears away, leak city. (this was the
case on the FF that i removed from the rieger).

last note on the 100mm flange swap: you dont need the springs when they go
into the older tranny, as there is no lsd to preload. keeping the springs
does nothing more than make installation difficult for no reason.


oh, if you're going to 90mm on a 100mm tranny for some reason, well, you
cant. the 90mm flanges do not have a properly machined surface to mate with
the non-sleeved 100mm seal on the newer style tranny. actually, its not that
its 'improper', its not even remotely the same... there simply is no 100mm
seal mating surface. there is also no way that i know of to get the revised
half of the tranny housing to accept the 90mm seal.

hth
Al