I am having a problem with my 2000 Chevy Impala LS transmission. On
occasion the tranny will shift hard while driving. Always happens when
the unit has been warmed up. It is not weather related. It will do it
on a cold as well as hot day. Out of the blue it will shift hard from
1st to second on up to overdrive. I can also hear a faint high pitched
noise like a hydraulic pump when it does it.
This started about 3 months ago. I had the tranny fluid and filter
changed 6 months ago at 70,000 miles. I had the tranny flushed and
filled filled a week ago hoping to cure but it still does it. It now
has 81,000 miles.
I took it to a transmission repair place while it was doing it and the
tech plugged his computer/scope to it and we went for a drive. he
could see the fault. The code indicated that the computer was puting
the tranny into "high Pressure" Limp home mode. He said usually there
are 2 codes present, one telling the computer something is wrong and
the other the computer telling the transmision what to do. Mine only
showed the code to put the trany in high pressure mode.
He was able to clear the code but it came back on a minute later. He
said he would need it for a day or so to figure out what is going on
and what needs to be fixed. My question to the group is will driving
the car in this condition cause even larger problems to the tranny and
does anyone have an idea what may be wrong. I'd hate to get the tranny
rebuilt if the only problem might be a wheel speed sensor.
Any suggestions, ideas? Thanks in advance.
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