Need Info,Suggestions,BTDTs for 86 5kcstq Rear Diff

["Douglas H. Quebbeman" <dougq@iglou.com>]

Good Morning, Listers!

I am having one of two problems I feared even before I bought this
car, my first Quattro (but my 8th Audi). Let me tell the story...

I did not notice this sound before I bought the car, of course.
But soon after the purchase (maybe on the way home with it), I
noticed a rythmic, metal-on-metal "low grind"-ing sound which 
would increase in pitch with an increase in vehicle speed. It
would pretty much disappear when letting off the gas, and it
is not as loud under acceleartion as it is when maintaining
speed on a level road.

I hoped that the source of this sound was merely a failed wheel
bearing. However, it seemed like the rear differential/ final drive
was also louder than it should be. So, I took it to our local
Audi dealer for a differential service.

They refilled the completely dry (!) differential with Audi G50,
and told me that it likely would continue to leak (BTW, it seems
like the sound and most of the leakage is coming from the left side
of the unit). So clearly, I have one or more seals that need to 
be replaced on the rear final drive. Additionally, I'd have to
guess that the primary noise that got my attention is the left
side bearing in the rear final drive.

How should I proceed? I have been considering the purchase of a 
shop hydraulic press and some gear pullers for a while, so I 
think I could do this repair if:

     1) I can get any needed spare parts like the bearings
     2) The ring and pinion gear aren't too worn (as I hear
         they are _very_ expensive).

But maybe it dosn't make sense to fix the Q right now... I bought it
for two reasons,

     1) I have always wanted a Quattro, and
     2) The Coup GT looked like it was going to cost a fortune to fix

I really need to make one of these vehicles drivable for the winter.
Should I look for a used tranny for the Coupe, and get it going? Or,
can I find a used rear final drive for the 5ktq?

I have been as impressed as can be with the expertise and info 
sharing I've seen here in the month or so that I was a lurker.
I sure hope y'all can give me a hand here...

--
-Douglas Hurst Quebbeman (dougq@iglou.com)
--
Current AUDIs:
74 100LS Automatic w/Weber 32DGV (in storage awaiting restoration) [#01]
77 100LS Automatic (in driveway, rusting)                          [#06]
84 Coupe GT (Running since Jan. '97 w/dry 5sp transmission)        [#07]
86 5KCSTQ (Finally, a Quattro!)                                    [#08]
--
"The large print giveth, and the small print taketh away."  -Tom Waits