Alternator, "rear transxle"

[Mike Arman]

>To: Kate FitchGerald <k_fitchgerald at yahoo.com>, quattro at audifans.com
>Subject: Re:  Alternator Woes
>Date: Mon, 1 Oct 2001 12:49:20 -0400
>
>> Oh, I forgot to ask.  What's the blue small wire from
>> the alternator for?
>
>Think of it as a "switch" for your alternator.  When your ignition is in the 
>on position, the blue wire supplies +12 to the alternator in effect turning 
>it on.  If +12 was supplied all the time, you'd have a consistant ~3 amp
draw 
>on your battery.
>



Alternator woes - someone grabbed my 4K book, but here's the basic method
of operation:


Power flows through the regulator TO the field coil of the alternator (the
moving part), via one brush, then through the field coil, then out through
the other brush to ground. Measure the voltage at the blue wire, you should
get battery voltage. (If not, why not? Follow it back through the regulator
to the power source.) If you do have battery voltage there, shut off the
car, disconnect the battery, and measure for continuity to ground from the
terminal on the alternator where the blue wire was connected. If you had
power, and you have continuity, the problem is either the armature (part
that doesn't move) or more likely the diodes - and you'll have to open and
rebuild the alternator. No continuity is either worn out brushes (cheap
fix), or alternator field is bad - open alternator and replace rotor, or
buy a complete alternator from a junkyard. These go for $20 at the
you-pull-it junkyards.




>From: "Jonas K." <jkarlsso at metabolex.com>
>To: quattro at audifans.com
>Subject: 91 80 automatic question
>

>Question: The seller says that his mechanic said the "rear transaxle"
needs replacing.
>Does this make sense?


None whatsoever. Run away.

Power flow is engine, torque converter, a LONG shaft through the
differential to the transmission (which is at the back of the power train),
then forward to the differential.

There ain't no such animal as a "rear transaxle", and if the seller is a
used car dealer, he's what is known as a lying sack of sh*t and  needs to
be shot. (Standard procedure, BTW.)

These transmissions are available used, but are not noted for their
robustness or long life.

If you can buy the car REAL CHEAP, it might be worthwhile if the rest of
the car is nice. Otherwise, pass.

The actual R&R isn't too awful, but you will find a lift and air tools to
be a great help. Also, getting that LONG shaft installed incorrectly
(there's a trick to making sure it is seated just right) will cost you the
torque converter and your new transmission. Ugh.


 I'm not at all familiar with automatic transaxle layouts, so it's
>gibberish to me. The car starts fine, but when put into drive, It makes a
horrible sound,
>and won't move. The transmission was replaced about 2 years ago, which
says nothing other
>than just that.


Yes, it says more than that - the transmission is good for 24 months or two
years, whichever comes first.



 will be doing the repair, and am looking at BTDT's on this particular
>part/problem. The seller indicated that it was a common problem.

Yup. Sorry. Let it remain HIS problem. These trannys are the VW type 3, and
are somewhat underspecified for the 4000 series cars and woefully
underspecified for the 5000s. Look for a standard shift car - they are much
less trouble.


 Also replacement parts
>costs (ballpark) for suspect components are welcome. 
>
>TIA, 
>Jonas
>90 CQ
>


Best Regards,

Mike Arman