My overdrive isn't doing its thing! Here's the situation:
I rebuilt the transmission and overdrive (Laycock OD) and
put them back in my 1955 Austin-Healey 100. It's installed
now, but not connected to the drive shaft. Engine starts and
runs. But the OD doesn't appear to produce any oil pressure!
When the engine is turning everything over in third gear, I
remove the plug on top of the OD actuating valve and see NO
oil being pumped. It seems like I have to get this fixed
before doing anything else, since that same oil supply goes
through the trans output shaft and lubricates several bearings.
Obviously I should have done better quality control before
putting the boxes back in the car. I'd like to do as much as
I can before pulling the whole assembly out of the car and
and separating the gearboxes. It seems to me that with the
trans in neutral I can turn the OD output flange, which
*should* drive the oil pump plunger. Here's the approach I've
got planned - any advice or suggestions would be most welcome:
1. Remove the plug on the bottom of the OD - hopefully oil
will pour out and run down my arm. Let the oil drain out and
probe oil passages with a piece of wire to be sure the pump is
getting a supply of oil. Is airlock a possibility?
2. Remove the plug at the bottom of the pump bore. I should be
able to insert a probe and touch the bottom of the pump plunger.
Turn the OD by hand and see if the plunger is moving up and down.
Could reveal a broken plunger return spring, or plunger roller
not in contact with driving cam. Could cam be installed backwards?
Nah, I'm not that stupid. Or am I? Also, when I remove this plug,
there should be oil in the revealed chamber.
3. Remove the side plate covering the pressure accumulator, and
remove pump output valve ball and spring. Check passages as far
as possible. If something is wrong with this valve, it would
explain no pressure. I could put the plugs back in the bottom
of the pump, add some oil, turn by hand, and look for oil coming
through this valve opening.
4. If nothing has been found so far, I guess I can try to pull
the pump body out from the bottom of the OD, to inspect the
plunger, roller, and return spring.
That's about it. If none of the above helps, the whole show from
the clutch back has to come out and the OD has to be separated
from the trans. No small task. The Laycock OD, taken as a whole,
is a remarkable unit, almost miraculous in its workings. But the
individual parts are really pretty simple, and at least the oil
pump should work. The old unit pumped oil, even though the OD
gears were trashed and the actuating pistons were frozen in their
cylinders.
Anybody have magical insights into this mystery? I really don't
wanna hafta pull those boxes apart!
Jim Beckman AT&T, Middletown, NJ att!mtqub!jeb
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