Re: Problem w/4kcsq

[James Marriott <marriott@micron.net>]

Whitson wrote:
> 
> I recently bought an '86 4000 CS quattro.
> 
> I would like some help diagnosing a couple of things I don't
> like.
> 
>         1.There is a hard pull to the left when the rear and
>           front differential is locked (but not when only
>           the front is).

First off, there's no manual lock for the _front_ differential. Notice
where the lights come on in the icon; not between the front wheels. The
knob controls the center (1) and center&rear (2) diffs. The car has
three open differentials:  one for the front axle (in the transaxle),
one for front/rear balance (in the transaxle), and one for the rear axle
(between the rear wheels). When the knob points straight up, all three
diffs are "unlocked" and the car is technically one wheel drive.

Turning the knob to the first position locks the CENTER differential.
This is ~equivalent to pulling the 4x4 lever on a '60s-vintage pickup
truck. That is, at least one front wheel and at least one rear wheel
must spin. This _guarantees_ that the AVERAGE speed of the front wheels
(RPM, not MPH) will be the same as the _average_ speed (RPM, not MPH) of
the rear wheels. Flipping the knob to the second position will leave the
center diff locked and will also lock the rear. This forces the two rear
wheels to rotate at the same speed (RPM, not MPH), and guarantees that
the AVERAGE speed of the front wheels (RPM, not MPH) will be the same as
the speed (RPM, not MPH) of the rear wheels.

Likely your pull is caused by wrong-sized/mixed or underinflated tires.
Do you have any trouble getting the diffs to unlock (on pavement) when
you're done playing?

>         2.When neither is locked (normal position) there is
>           a shake in the wheel at speeds above 60 mph.
>           This isn't present with differentials (both) locked.
>           I recently read a post that this could be the drive
>           shaft not balanced. I haven't checked this out yet
>           but would like to know of anybody else's experience
>           in solving this dilemma.

First get the pull straighted out. Then assume a tire balance problem.
Believe me, you don't want trouble with the driveshaft . . .

hth,
James
'87 4kq
'86 4ks
'64 Falcon