Scott Sawyer wrote:
>
> Towed the STS Civic to an event this weekend on an open trailer. When I
> got there the front of the trailer and car were covered were covered in
> what I thought was oil. Upon further investigation it looks like I'm
> losing ATF through the overflow hose.
The trans is overheating and blowing fluid out the vent hose.
Level had not changed before the
> trip. I used to tow in overdrive per the dealer's suggestion. I began to
> get concerned about too much heat in the transmission while towing (it
> started shifting very hard while towing for long distances)
The hard shift is caused by the TCU (transmission computer). The TCU has
detected a torque converter clutch slip (which is what caused the
transmission to run hot and blow fluid out the vent) and set a DTC
(Diagnostic Trouble Code, most likely a P1870 code for "transmission
component slip"). When the computer sets this DTC it will put the
transmission in "failure management mode" which is high line pressure and
thus the hard shift. The TCU will reset on the next ignition cycle. To
reset the code it must see in excess of 150 rpm of torque converter clutch
slip for more than 10 seconds.
> I've also noticed in the last 2-3 weeks that when the tranny
> is cold it sometimes slips when first starting out in first gear. The
> truck revs up then feels like it drops into gear and jerks forward.
>
> Any ideas?
Yep, you have a low line pressure condition which will cause both of these
problems.
> Am I turning the trans too fast for too long and pumping the
> fluid out?
Nope.
> Should I go back to towing in overdrive (seemed to work
> pretty well on the way home today)? I'm planning to take it to the
> dealership in the next few days, but I wouldn't mind having an idea of
> what might be wrong.
Tow in OD but after you get the transmission fixed. Is it still under
warranty at the dealer? You _are_ going to need an overhaul.
Steve Hoelscher
#27 DSP
Owner: AAMCO Transmissions - Decatur, Alabama
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