Re: '93 90CS automatic transmission problem

[Elliott Potter <epotter@abraxis.com>]

Daniel Adams wrote:
> 
> My addition to the recent '93 90 questions...
 
Man, this is scary!  I'm glad I've already dumped bunches of money into
mine (or maybe I shouldn't say that?)

> At first I thought the problem only occurred when the motor was warm (i.e.
> driven from work).  But now I think anytime the car gets above 45 mph,
> therefore going into top gear, shortly after being started that the anomaly
> happens.  The true sign is when the motor shoots up 500-1000 rpm higher
> going into overdrive.  At this point I know the transmission is in the
> bizarre state.  Now it requires high rpm to shift up to the next gear and
> shift down if you let the revs go too low (2500 rpm).  Since this problem is
> not reproducible the dealer had no solution and proposed that it is a
> computer problem.  They suggested a temporary fix of restarting the car
> (therefore, computer).  This does resolve the problem for that instance of
> the problem.
 
So after you've shifted from 3rd->4th once, the RPM's shoot way up every
time it shifts?  (trying to clarify)
If it usually seems to involve that 3rd->4th shift what you might try is
driving with the shift selector in "3" instead of "D" and see if that
changes the way it behaves.  If it does, then you could well have some
problem related to 4th gear--I don't have my manual handy but I can look
into what sorts of valves/sensors are related to each gear.  The
transmission computer has a number of failsafe modes, but I also think
that it has a few 'contingency' modes, where if it senses something
wrong (i.e. something sticking) it will try to correct the problem--that
could be what is happening.  Have you had your dealer check the
transmission computer for error codes?  I'm pretty sure that it stores
error codes (not positive though...it seems that it would, considering
every other *#$ computer in the car does).

> On Monday, I had a transmission service (filter/fluids) and this has had no
> impact on the situation.  I have also, found that leaving the car in sport
> mode (requires higher rpms to shift) and babying it that first time it
> shifts into 4th decreases the frequency of the problem.  But I feel that
> there may be a valve sticking or torque converter problem.  Any ideas would
> be appreciated.
 
When the fluid was changed, did you (or whoever) notice anything bad in
the fluid?  Metal shavings?  Springs?  Teeth?  Cat hairs?  Also, you
might give the new fluid a chance to work into things; if it seems to
get a little better in the next few hundred miles, you might try
changing it again (i.e. if something got gummed up, keeping the fluid
clean will help clean stuff out).

> regards,
> Daniel

Good luck!
-- 
Elliott