Tiptronic transmission

[Steve Sears]

Jim,
That system is probably very similar to, if not the same as, the Fichtel &
Sachs "Saxomat" clutch system found in.....[returning to closer-to-Audi
content].....Auto Union/DKW's.  The clutch had a combination of centrifugal
weights and standard clutch bits - the vacuum supply, from the intake
manifold, was switched through a valve that was electrically actuated by a
switch in the base of the shift lever and actuated the clutch release on the
transmission.  The centrifugal weights were there to ease the clutch back
in, as the on/off of the vacuum would produce somewhat of a violent
engagement.  One tricky part was that on a downhill, you had to keep your
foot on the gas, for if your foot was off, you'd sail down the hill with the
clutch disengaged and then at the bottom, when you put your foot on the gas,
the clutch would suddenly mash together.  I once bought a servo for a
Saxomat from a guy on eBay - he said that it was originally from his dad's
long-departed car, and his dad referred to is as the "Automatic Headwind"
system.
Auto Unions (1000cc variety, not the Juniors) also had a "freewheeling
device" that was engaged by a lever.  As they were 2-strokes, using engine
braking will starve the engine for oil, and could sieze it in short order.
The freewheel allowed free-running of the transmission (as that on a
bicycle), and I've heard that with careful application, you could do your
shifting while freewheeling.
Finally, for a chuckle, if you ever come across someone selling old Audi
brochures, check out the old brochure that is entitled something like "50
Answers to questions about the Audi 100" (or /5000?) - One question is if
the car had an Automatic transmission option, and the response was that it
was available "for those too uncoordinated to drive a standard
transmission".
Cheers!
Steve Sears
1987 Audi 5kTQ
1980 Audi 5k -
1962 and '64 Auto Union DKW Junior deLuxes
----- Original Message ----- 
> From: Jim Dupree <jdupree914 at sbcglobal.net>
> Subject: Re: Re: Tiptronic transmission
> To: Richard J Lebens <rick-l at rocketmail.com>, quattro at audifans.com
> Message-ID: <20050825223846.55033.qmail at web81405.mail.yahoo.com>
> Content-Type: text/plain; charset=iso-8859-1
>
> VW's Autostick and Porsche's Sportomatic were
> essentially the same. Had both a torque converter and
> a clutch. Torque converter was between the engine and
> the the clutch. The clutch was operated by a large
> vacuum servo. A solenoid valve control vacuum to the
> clutch servo. A micro switch in the base of teh shift
> lever controlled the solenoid valve.
> Slight movement in the shift lever opened the micro
> switch with opened the solenoid valve with allowed
> vacuum to the servo to disengage the clutch allowing
> you to shift gears. Since the torque converter was
> attached directly to the engine it smoothed out the
> abrupt engagement of the clutch and allowed you to
> come to a stop. The rest of the trans was typical 4
> speed manual.
> Common failures (quite common):
> Switch in shift lever meaning it could disengage the
> clutch anytime anyplace or not disengage at all. (in
> high school I helped my friend older brother tow his
> Autostick beetle to the dealer 3 different times. Ran
> fine but would not engage the clutch.)
> Servo diaphragm would fail.
> Not enough engine vacuum to disengage the clutch.
> Sudden vacuum draw would kill the engine.
> Linkage to clutch from servo would fail.
>
> Torque converter and engine share there oil supply.
> Adding heat to the already stressed engine and dirt
> from the engine to the torque converter. At least on
> the Porsche there was approx 10 qts of oil to share.
>
> Not a bad idea but poor implementation.
>
> Jim