Hi Rick,
That is exactly the check that I use to determine if the pump plunger is
moving up and down correctly. It normally moves about 3/16 - 1/4" and I
suspect your diagnosis is correct.
Unfortunately there really is no option but to remove the gearbox. I have
actually removed an overdrive unit with the gearbox in situ but it was
really difficult to reassemble and not worth the trouble.
If you remove the overdrive pump, be sure to remove the non return valve
first, you can actually see the cam. May be worth the trouble to confirm
your diagnosis. Reinstalling the pump can be a bit of a pain without the
correct guide screws.
Good luck.
Michael Salter
http://www.netbug.net/blogmichael/?p=445
-----Original Message-----
From: healeys-bounces@autox.team.net [mailto:healeys-bounces@autox.team.net]
On Behalf Of Rick Swain
Sent: Wednesday, July 15, 2009 7:27 PM
To: Healey List
Subject: [Healeys] Overdrive Problem
I finally have my '59 BN4 back on the road with everything working except
the
overdrive. I checked the electrical side of things and it works fine.
Solenoid engages and operating lever is adjusted correctly. I moved on to
the
hydraulics. I removed the operating valve and ran the engine in gear. I
discovered that no oil was being pumped into the valve chamber. The gearbox
was rebuilt by a friend who has worked on many British gearboxes. The
overdrive was not disturbed because it had been working perfectly
previously.
The problem that prompted the rebuild was jumping out of gear.
It has been suggested that when the gearbox and overdrive were reassembled,
perhaps the oil pump cam was installed backwards. To check this I removed
the
oil drain plug, strainer and the plug that screws into the oil pump body. I
then inserted a screwdriver against the oil pump plunger. I hoped it was
stuck
in its lowest position. I tapped upwards but got a very solid clunk. The
plunger spring seems to be doing its job of forcing the plunger up. With the
screwdriver against the plunger I turned the right rear wheel. I thought
that
if the cam was installed correctly I should feel the oil pump plunger moving
up and down as the cam rotates. I can feel just barely perceptible movement
-
which to me indicates the plunger is not in contact with the cam. Am I
correct? How much movement of the plunger should there be? Am I going to
have
to pull the gearbox to reinstall the oil pump cam right way round?
Thanks for any help or advice.
Rick Swain
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