Suibaru Impreza 2002 Automatic Transmission hesitation

Per online research learned that my problem of transmission hesitation seems
prevalent in Subarus. It is intensified by use of A/C but happens some
without its use.
There seems to be several possible reasons and diagnosis is not easy and
repair if it is the ECM can be quite costly - so they say. A mechanic told
me I should not go to my Subaru dealer but rather a transmission shop for a
correct diagnosis. I am not under warranty - bought the car used (had been a
leased vehicle) - its record of service from "Carfax" showed a "shift
linkage repair" by my dealer just before I purchased it. In September 2006 I
complained about the problem and they did a tune up - sparks - wire - coils.
It was OK throughout the winter - seems worse in this CT hot humid weather.
Where would you go - dealer or transmission shop for an accurate diagnosis?
Thank you.
Greta

"Greta" <sarek-gmc.DeleteThis@worldnet.att.net> wrote in message
news:0raui.407693$p47.218397@bgtnsc04-news.ops.worldnet.att.net...
> Per online research learned that my problem of transmission hesitation
> seems prevalent in Subarus. It is intensified by use of A/C but happens
> some without its use.
> There seems to be several possible reasons and diagnosis is not easy and
> repair if it is the ECM can be quite costly - so they say. A mechanic told
> me I should not go to my Subaru dealer but rather a transmission shop for
> a correct diagnosis. I am not under warranty - bought the car used (had
> been a leased vehicle) - its record of service from "Carfax" showed a
> "shift linkage repair" by my dealer just before I purchased it. In
> September 2006 I complained about the problem and they did a tune up -
> sparks - wire - coils. It was OK throughout the winter - seems worse in
> this CT hot humid weather.
> Where would you go - dealer or transmission shop for an accurate
> diagnosis?
> Thank you.
> Greta

Take it to an auto trans specialist, they would be able to diagnose it for
you. There are numerous possible causes such as low line pressure, which
could be caused by a valve body problem, degraded ATF, blocked filter in the
valve body, faulty ATF temp sensor etc, faulty throttle position sensor
(unlikely though as it would cause other problems). It's very unlikely the
TCU would be the root cause of the problem as they are pretty good at
diagnosing themselves and would flag an error. Auto transmissions are
usually beyond the capabilities of most mechanics, so go to somone that
repairs them all the time .

James