RE: Replacing tires on quattro

["TM" <mizutanit@mindspring.com>]

Steve,
I've popped the hood, but haven't had the luxury of examining the
drivetrain in detail on a lift, with an experienced Audi mechanic
pointing out what all of the things are. I lack the "whole picture"
knowledge of how these things work, which is one reason I'm going to
compile a small library of books detailing all of the systems, starting
with the Bentley manuals and the Bosch FI books.

BTW, the Talon does have a center diff. My Pathfinder does not have a
center diff, IIRC.

Funny how Subaru and Audi are the only ones with fairly decent AWD
systems that are actually durable. Mitsubishi's system is definitely
not. I don't know about Toyota's, as the All-Trac Celica and Camry are
two very rare cars. Nissan's AWD system never made it to the States,
although it is used to good effect in the Skyline GT-R and the Pulsar GTI-R.

Maybe the transfer constitutes the part that "turns" the tranny output
so that the rear drive can work. The rear driveshaft does come out of
the transfer case on a Talon. Of course, the only good thing I can say about
the Talon is that it's AWD and it doesn't use Pentosin! :-)

TM

-----Original Message-----
From: owner-quattro@audifans.com [mailto:owner-quattro@audifans.com]On
Behalf Of Buchholz, Steven
Sent: Wednesday, November 10, 1999 8:08 PM
To: 'qlist'
Subject: RE: Replacing tires on quattro


... one might think that you've never popped the hood on a quattro!  :-)

Unlike most other FWD manufacturers ... even VW ... for some reason Audi
adopted a standard of using longitudinally mounted engines in their FWD
vehicles.  This decision really paid off for them when they decided to build
an AWD platform as it didn't take too much to make the output shaft of the
transaxle hollow, install an open differential at the back end of the
transaxle and feed the shaft that drives the front wheels down the middle of
the transmission.  This made it a simple matter to add a propeller shaft
from the back of the transaxle (actually one of the output shafts from the
center differential) to the rear differential much like a standard RWD
vehicle ... voila, AWD!

I have to admit a bit of ignorance about what constitutes a transfer case
... but I didn't think that it included a center differential typically.
That may not be true though as I think the BMW 325ix used a transfer case.
In any event, of the quattros I'm familiar with the drivetrain is one of the
most robust parts of the car, and is one of the reasons I've chosen to buy
so many of them.  There is one odd standard maintnance issue that can be
neglected, that being the 15K mile service interval on the U-joint in the
propshaft, and IME and from what I've seen on the q-list the quattro
transmission's synchros seem to be a bit of a weak link.

HTH!
Steve Buchholz
San Jose, CA (USA)

> -----Original Message-----
>
> It's funny you say that, because my Eagle Talon TSi AWD has
> a transfer case. However, it's not a part-time system, but
> full-time AWD. How does Quattro distribute torque front and
> rear then? Are there two output shafts from the tranny? One
> going sideways to the front axle and one going back to the
> rear?
>
> If Audis truly don't have transfer cases, maybe that's a good
> thing, because the DSM AWD cars have a tendency to destroy
> transfer cases at a regular rate- I'm on my third, with only
> 61k on the odometer. DSM AWD systems just plain suck.