The fla****ng OD light is a sign that something is wrong.... left
unattended,
transmission problems have a way of snowballing.... At the time that the
light is fla****ng, the transmission goes into what might be considered a
"fail safe" mode. Line pressure maxes out in an attempt to keep clutches
from slipping (hence the harsh ****ft feel) and the PCM (bless it's niave
little heart) firmly believes that the owner is going to say "Uh-oh...
better get that checked".
Without knowing which trans it is, total miles on the car, how many miles
has it been driven "hurtin'"... codes... maybe some pessure and "what
gears
do I have" kinds of testing.. it's a crap shoot to come up with an answer
that really means anything.. Is the concern very, very intermittent - or
does it happen very regularly? So many questions, I know... but a good
diag
needs to have them asked and answered.
Occasionally, we see these kinds of things as an electrical concern...
more
often than not, they are mechanical or hydraulic problems. If it is an
internal problem, the condition of the rest of the trans needs to be
considered... If it's getting long in the tooth, the wise choice might be
a
rebuilt.... If the trans has a lot of miles, going in and fixing only the
obvious problem could leave an owner with a ticking time bomb on his
hands.
FWIW.... on both the 5R55 and the 4R70, I'd have to say that I see more
direct clutch failures than anything else.
A good trans tech will start with fluid level and condition... a code
scan... and (hopefully the trans will be acting up for this part) a road
test - he'll be checking what lever positions work as they should....
whether there is engine braking when it should happen... up****ft and
down****ft points. This part can be tough to describe... I don't know what
I'm looking for.... but when I find it, I'll know.... Pressure testing can
be very im****tant as well.... Using this info, the appropriate band/clutch
apply charts... a savvy trans guy should be able to nail the cause of the
failure 90% of the time.
Not the answer you're looking for, I know... but the automatic trans is a
pretty complex beast...
FWIW, the only "rebuild" kits that I know of come only with the fiber and
steel plates and all the "soft" parts (seals, gaskets sealing rings...)
and
might not contain what it is you actually need..
Afterthought... I've heard of worn servo bores in the 5R55 giving grief...
Haven't come across one myself, but there are aftermarket kits available
to
repair this condition.
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