UPDATE (Fixed): 1994 NY 3.5L Harsh downshift 2-1 when slowing to a stop.

REF: 1994 NY 3.5L Harsh downshift 2-1 when slowing to a stop. 08-31-2002.

Since my original posting approximately 1 year ago on Aug 31, 2002, I've
done a couple of things.

1. In September, 2002, removed and cleaned the main cable connectors at the
Powertrain Control Module (very contaminated, located on the passenger side
front engine compartment, low) and the Transmission Control Module (fairly
clean, located on the driver's side front engine compartment). This seemed
to improve the shifting but not fully. Approximately a month of driving
after the cleaning (coincidently when the weather became cold) the
bone-jarring "bump shift" problem went away.

2. In mid July, 2003, the transmission had trouble picking a gear when
slowing from 60 mph to 20 mph then back to 60 mph, in freeway traffic from
the airport, on a warm evening. And later I noticed a tendency to sometimes
hard shift (similar to the "Bump Shift" but much less severe) when coming to
a stop from second gear to first during other trips. This time I R&R'd the
INPUT SPEED SENSOR and the OUTPUT SPEED SENSOR located on the driver's side
of the transmission. The transmission immediately began shifting smoother
than it ever had and continues to be trouble free! Total cost of sensors:
$50.

Please be aware that the troubles that plague the Chrysler 4-speed
electronically controlled transmission, are NOT ALWAYS an indication of the
need for a transmission rebuild or replacement, as some dealers would have
you believe! I'm very glad I declined the recommendation from the Kirkland
Chrysler Jeep, Inc (Kirkland, Wa.) service department. I know that it's
difficult to diagnose correctly all the time but I believe that this
recommendation (the most expensive option) was not worth the $90 they
charged. And, since most of the newsgroup postings blame either poor
transmission fluid change schedule or poor choice of fluid name brand, for
this same issue, I hope that this finding will help others facing a $3,000 -
$5,000 transmission repair recommendation, to try cheaper options first!

--
Bill Hodgson


===============REFERENCE POSTING FOLLOWS==============
From: Bill Hodgson ()
Subject: 1994 NY 3.5L Harsh downshift 2-1 when slowing to a stop.


View this article only
Newsgroups: rec.autos.makers.chrysler, rec.autos.tech
Date: 2002-08-31 23:09:05 PST


1994 Chrysler New Yorker with 42LE (A606) 4 sp OD automatic transmission.
Shifts from 2nd to 1st when coming to a stop cause the car to come to
immediate "almost-full" stop as soon as the vehicle speed gets under 8 mph.

Asked the Kirkland Chrysler Jeep, Inc service department for the diagnostic
codes on the Transmission Computer Module and they found the following:
1. No codes
2. CVI for L/R very high (L/R =102; 2/4 = 41; O/D = 87; U/D = 39.)
3. transmission fluid is very burnt.
4. trans cooler lines are leaking.

Their recommendation is to replace the cooler lines and either overhaul or
replace the transmission.

The trans cooler lines do leak (since I bought the car) but it's so small
that the fluid level has not changed much from the FULL line in the 2 years
that I have owned this car. (Never had to add yet since it has not lost even
a 1/4 pint).
The transmission fluid seems to be normal when compared to other car's.
If the car is accelerated before the 2nd to 1st downshift, the shift from
2nd to 1st gear is normal.

I suspect that this condition noted in #2 above, can be caused by a slow
responding solenoid(s) in the trans. The manual shows that the L/R and 2/4
solenoids must be energized for first gear. So the sequence from Direct Gear
down to 1st gear goes as follows;
3rd (Direct) = 2/4 solenoid.
2nd = no solenoids
1st = L/R and 2/4 solenoids.

So if both solenoids remain de-energized, and a residual pressure is left in
the Reverse circuit, don't you have the same setup as a "mini-reverse"?
(REVERSE has both solenoids de-energized while hi-pressure is routed to
REVERSE.)
Could the MANUAL VALVE be leaking and cause this? Is there a typical part
failure for this 2nd-1st gear downshift problem?

If the shift is normal during acceleration, is there a problem with the
speed sensors that could create this condition because the TCM and PCM are
not in-sync?

Do the CVI readings indicate a particular failure?

Bill Hodgson