433
Solving
malfunctions with the V8 overdrive
This note brings together information from several postings
on the V8 Bulletin Board of members' experiences with overdrive
malfunctions. The most recent posting was from Marcus Schopen
from Germany in August 2011. (Aug 11)
Marcus
Schopen raised his query saying "over the last few
days my overdrive doesn't disengage as long as the gear oil
is cold. I can flick in the overdrive in the 4th gear, but can't
disengage in 4th gear. If I change to 3rd gear while the overdrive
is engaged, it doesn't disengage until I speed up in the 3rd
gear. The strange behaviour stops after some miles when the
engine temperature reaches "N". Then the OD is working
very well and it disengages quickly.
Today I changed the three O-rings, cleaned the solenoid and
control valve, changed the filter (sludge on the magnet on the
cover plate under the filter) and filled up with new gear oil
Penrite 40). The old gear oil was really black. I changed the
gear oil last year and drove about 10.000 miles without any
problems since then. After today's changes the OD flicks in
more quickly, but it still doesn't disengage with cold oil.
Electrically seems to be everything well. The solenoid is working
(I can hear the click), the OD turns off electronically if I
change from 4th gear to 3rd gear |
(checked
with a test lamp) or if I turn it off by the switch when in
the 4th gear. Any ideas?
Victor Smith
responded saying "on the two occasions I have had problems
with my overdrive over the last 36 years, replacing the solenoid
has been the cure. It's a service operation that can be carried
out without removing the gearbox or engine and a replacement
solenoid is not an expensive item. At the time of the last solenoid
replacement in 2009 the symptoms were an overdrive cycling in
and out as I drove along. The difficulty was traced to the overdrive
solenoid. Replacing the solenoid with one supplied by B&G
(see their online spares catalogue) and cleaning the oil and
filter at the same time, cured it and now the overdrive operates
very smoothly. Popping the key word "overdrive" in
the V8BB search box and clicking the archives box uncovers two
threads with my comments above.
I notice
that in the latest issue of Safety Fast! (August 2011 issue)
on the "Problem Solved" page the first question addresses
a member's query about a malfunctioning overdrive on an MGBGT.
The technical queries are answered by B&G and in that article
Ron Gammons mentions several checks you can make including changing
the oil and cleaning the OD filter. Just go to page 42".
See
a copy of this article
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