Re: drivetrain play

[Luis Marques <marques@rtis.ray.com>]

From: Martin Pajak <quattro@rogerswave.ca>
> Some of the play is from gears themselves and CV joints (should be
> very little) and most of it is from tranny and rear diff mounts. 
> Check those first and than go to the CV's.  At least you can fix those
> a lot easier than gears in the tranny and rear diff. HTH
> 
> Brett Dikeman wrote:
> > While pulling off a wheel, I noticed what seemed like a substantial
> > amount of play in the drivetrain.  With the car in 1st and handbrake
> > on, I was able to rotate a front tire roughly 1/8th of a full turn. 
> > This turn was accompanied by clunks from the rear and a quieter
> > clunk from up front, I presume from the diffs and such.
> >
> > Is this much play normal?  This "play" is noticeable under certain
> > circumstances, such as starting up in 1st sometimes; most usually,
> > under shifts.

I have also notied this.  Even with good tranny mounts.  There really is
that much play in all the differential gears.  I really notice it when I
turn into a steep driveway.  As soon a the first wheel goes up into the
driveway, there is a small period where the car stops (freewheels) while
the engine makes up for the backlash in the gears and then starts to
pull the car up the hill.  If everything checks OK, I would say learn to
live with it.  I don't notice this play when starting or shifting or any
of that - just when there is a sharp transition from a steep grade into
level ground (or vice versa) while turning.  It does make sense when you
realize that on a 1st gen. quattro system there are a total of _four_ 90
deg. gears meshing between the front and rear wheels (and that doesn't
include the actual transmission).  All the little backlash in each gear
simply adds up (especially the center differential).  On a straight line
the play isn't as noticeable because there are only two 90 deg. gear
meshes between the transmission and any other wheel.

Luis Marques
'87 4kcsq