1997 civic transmission or ecu problem ??

Having problems with a 97 Civic DX with Automatic Transmission. 60k
Miles on the car. One owner.

The symptoms

Seems to drive fine when cold. Transmission shifts fine.
After approximately 5 miles, transmission shifts a harshly. Seems to
not know what gear it should be in (no codes at this time)

Then after completely warm, transmission wont drive at all (like its
in neutral)
Can shut the car off at this point and it may or may not allow
transmissin to engage. keying ignition on several time will allow the
car to drive but will not shift properly. Code will appear only when
transmission slips (P0700 and P0715)

Have followed troubleshooting chart from Honda and Mainshaft speed
sensor reads 550 ohms of resistance and wiring between pcm and sensor
are good.

Following troubleshooting instructions (from Honda)indicate I should
try a known good PCM (ecu) and follow troubleshooting for P0720
(Output speed sensor).

I am not the type of person to purchase parts unless im sure they will
work (like ECM).

I do not believe faults generated by ECM will lead me to the solution
since the fault was generated after harsh shifting and eratic acting
transmission. see first paragraph when code was generated. What do you
think?

Transmission started to whine before slipping. Makes noise (growling
from time to time). Hard shift from time to time. and makes noise
from time to time.

When I reboot, sometimes it will go into 2nd and go....and sometimes
it will drive in 4th and go.

I have read about replacing linear solenoid when obtaining codes p0700
and p0715
after flushing transmission. I actually am hesitant to do this since
the fluid is $50 and LS is $150 and Parts manager at Honda says this
does not always work and also, since my sypmtoms go beyond the harsh
shifting (no drive situation)


Just trying to get opinions before dumping $s into a worthless trani.

Tried to buy a Honda manual from Honda, they did not have one and gave
me number to publisher. so any help with resistance perameters of
output speed sensor would help. Also pin numbers at connector 25 at
ECU (and wire color)

Not sure if i can have ECU checked someplace???

Oh, one more clue ... Fluid seems a bit dark, but am unsure of flid
color of honda trani flid. Original flid in trani, never has been
flushed or changed.

 

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Matt,

Since your tranny fluid has SEVEN years of accumulated moisture, dirt,
and friction material, it makes sense that you should start with the
obvious / cheap fixes first.

Here's a snip from a previous post: You run it until it's hot, unscrew
the plug, drain 3.5 litres out. Wipe shavings off plug, reinstall plug,
top up with 3.5 litres of Honda Z1. One week / 100 miles later you do it
again. Use a painter's tray to catch it, and save it in a 4 litre jug
for recycling. You don't even need a special wrench, just a 3/8" socket
handle.

'Curly'