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Re: quattro drive questions


>  Awhile back (2 weeks ago), I told my story about my recently purchased
>86 4k csq. When I had it up on blocks and in gear, the front wheels
>would spin, but the rear wheels didn't. I was concerned: this is
>supposed to be perm 4wd, right? With the center or rear diff locked,
>everything was fine, all four spun.
>  I got both responses to my concern. Some told me my car was having
>trouble, others said it was normal. Well, last weekend I bought a '87 4k
>csq ($600 US 140k miles, beautiful, messed up rear quater), drove it
>home (40 miles) fine, no noises. Put it on blocks, same thing! The rears
>wouldn't spin unless the center or rear diff was locked! Now either I
>had two quattros with the same problem, or this is normal.
>Can someone set me straight? Why are they behaving this way?

The same was me purchased year ago my '85 Audi 80 Quattro. I even thought
that there are visco coupling in transmission. To understand more about
AWD I would recommend you have a look at http://www.eskimo.com/~eliot/awd.html -
the best article on this subject I've ever read.
As for central diff it is his normal behavior to transfer all power to
the driveshaft which has less resistant. Turning front wheels it has to
turn only two small light driveshafts. Turning rear wheels it has to turn
big heavy driveshaft, rear diff, and again two small driveshafts. Gess what
side has less resistant:) When you lock center diff it will turn front
and rear axes with the same speed.

>And while you're at it, can someone give me examples of when you would
>lock the rear instead of the center? I'm a newbie to 4wd, let alone
>qwattro drive.

You can not lock rear diff without locking center. So you have two options:
- center diff locked
- center and rear diff locked.
IMHO second option will be helpfull only in a deep mud. As for first - sometimes
I am driving with center diff locked in rain or snow. Seems to be that car
more stable this way. Maybe somebody more experienced can confirm or refute
this idea.

>Thanks a bunch!

With best regards,

Kiev, Ukraine
'85 Audi 80 Quattro

PS I've thought that '87 4kq has to have torsen as center diff...